Generation, verification and reproduction of a digitized writing

ABSTRACT

A digitized writing is recorded in a digitized writing record including at least the position of each point of a writing in coordinates relative to a coordinate of a previous point thereof and time. The digitized writing record may be converted to image format.

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/127,793 filed Apr. 22, 2002, which claims the benefit of thepriority of:

[0002] U.S. Provisional Application Serial No. 60/351,266 filed Jan. 23,2002,

[0003] U.S. Provisional Application Serial No. 60/352,901 filed Jan. 30,2002,

[0004] U.S. Provisional Application Serial No. 60/359,558 filed Feb. 22,2002, and

[0005] U.S. Provisional Application Serial No. 60/366,061 filed Mar. 19,2002.

[0006] The present invention relates to a digitized writing and, inparticular, to a method and apparatus for the capture, generation,verification and/or reproduction thereof.

[0007] A portion of the disclosure of this patent document containsmaterial which is subject to copyright protection. The copyright ownerhas no objection to the facsimile reproduction by anyone of the patentdisclosure, as it appears in the Patent and Trademark Office patentfiles or records, but otherwise reserves all copyright rightswhatsoever.

[0008] The world is long past the time where the economy and societywere primarily local and everyone personally knew everyone heencountered, such as in business. As commerce expanded geographically,means other than personal knowledge arose to confirm identity andbusiness. In modern times, with worldwide communication andtransportation, business and commerce has become global. In addition,with telephone, undersea cables, radio communication, communicationsatellites, cell phones, facsimile, e-mail, and the Internet, businessand commerce has become virtually instantaneous, irrespective ofgeographical location. Thus, means of confirming identity and businessvirtually instantaneously and over long distances have been developed.

[0009] Among these are various digital signature transmission andverification protocols, such as public key infrastructure (PKI) which isa form of electronic signature that utilizes encryption codes linked tospecific computers and other hardware for providing confirmation and/orverification of users over the Internet. Commercial PKI includes, e.g.,those available from VeriSign, Inc. located in Mountain View, Calif. andDigital Signature Trust located in Rockville, Md.

[0010] One disadvantage of the available PKI systems is that they lackmobility because the PKI code or key is associated with a particularequipment with which it is registered and must be used. Security andauthentication comes in part from the equipment that is registered tothe authorized user (person, company or other organization) inconjunction with a public key. Because PKI does not utilize biometricdata as verification, anyone gaining access to the registered equipmentcould engage in a public key transaction and appear authentic.

[0011] Certain retail transactions such as credit card purchases nowutilize an electronic pad and pen to capture an image or graphic of thesignature of the person engaging in a transaction, but the signatureimage is for credit authorization and is not biometrically verified asbelonging to the authorized cardholder. Such digital signature imagesare typically in an image format such as the JPEG, TIFF or the like, andtypically require a substantial memory capacity to store, e.g.,typically about three kilobytes. With millions of transactionsoccurring, the amount of memory capacity needed to store such digitalsignature images quickly becomes quite large, if not prohibitive.Moreover, because such images can be “cut and pasted” electronically,they can easily be falsified by being copied into a different documentor file, and so because the copy cannot be distinguished from theoriginal, image signatures cannot offer satisfactory security andauthentication.

[0012] Other digital signature arrangements also utilize signature pads,e.g., U.S. Pat. Nos. 6,064,751, 5,818,955, and 5,195,133, andcharacterize certain characteristics of the signature, but all requiresubstantial memory for recording the signature and/or itscharacteristics typically, most require 2-4 kilobytes (2000-4000 bytes).Even in a known example of a vector method, the starting point canrequire as many a 5 bytes or more and each subsequent point can requireas many as two additional bytes, so that a complete signature stillrequires as much as 1-3 kilobytes of memory. Known conventionalsignature digitizing schemes are based on averages and/or statisticaldata of various signature characteristics typically derived from aplurality of signings, and so biometric data of any particular signatureis lost and is unavailable.

[0013] Accordingly, there is a need for a method for digitizing asignature that typically requires less than 1 kilobyte of memory, andpreferably less than 500 bytes of memory for a typical signature.Moreover, it would be desirable for such method to be compatible withinexpensive hardware interfaces and for use over the Internet, as wellas in other non-Internet utilizations, and to retain certain biometricdata of the signature for use in signature authentication.

[0014] To this end, the present invention comprises a method forgenerating a digitized writing record from a writing signed on a writingsurface comprising:

[0015] (a) recording the location of a starting point of each stroke ofthe writing, wherein the starting point of a first stroke defines thestarting point of the writing;

[0016] (b) recording point locations on the writing surface until thestylus is lifted off the writing surface, thereby defining a stroke ofthe writing;

[0017] (c) repeating steps (a) and (b) for each subsequent stroke of thewriting until the writing is completely written;

[0018] (d) determining a number of bits for storing the point locationsof the writing and storing the determined number in the digitizedwriting record;

[0019] (e) storing in the digitized writing record a time or rate atwhich the recorded points are recorded;

[0020] (f) storing in the digitized writing record the locations of thestarting points of each stroke; and

[0021] (g) coding in the determined number of bits the locations of thepoints of each stroke in values relative to a starting point or animmediately previous point thereof and storing same in the digitizedwriting record.

BRIEF DESCRIPTION OF THE DRAWING

[0022] The detailed description of the preferred embodiments of thepresent invention will be more easily and better understood when read inconjunction with the FIGURES of the Drawing which include:

[0023]FIGS. 1A, 1B and 1C are examples of signatures that may becaptured and digitized and/or reproduced from a digitized signature;

[0024]FIG. 2 is a schematic flow diagram representing the generating ofa data record including a digitized signature;

[0025]FIG. 3 is a schematic diagram representing an example of a dataword representing a digitized signature record;

[0026]FIGS. 4 and 5 are schematic flow diagrams illustrating a methodfor generating a digitized signature and for verifying same in relationto a transaction;

[0027]FIG. 6 is a schematic flow diagram illustrating a method forgenerating a digitized signature;

[0028]FIG. 7 is a schematic flow diagram illustrating a method forcomparing and/or authenticating a digitized signature;

[0029]FIGS. 8A through 8D illustrate examples of screen displays usefulwith the digitized signature apparatus and method described;

[0030]FIG. 9 is a schematic flow diagram illustrating a method forreproducing a digitized signature;

[0031]FIG. 10 is a schematic block diagram of apparatus for capturingand generating a digitized signature and for verifying same in relationto a transaction; and

[0032]FIG. 11 is a schematic flow diagram illustrating a votingarrangement employing digitized signatures.

[0033] In the Drawing, where an element or feature is shown in more thanone drawing figure, the same alphanumeric designation may be used todesignate such element or feature in each figure, and where a closelyrelated or modified element is shown in a figure, the samealphanumerical designation primed may be used to designate the modifiedelement or feature. Similarly, similar elements or features may bedesignated by like alpha-numeric designations in different figures ofthe Drawing and with similar nomenclature in the specification, but inthe Drawing are preceded by digits unique to the embodiment described.For example, a particular element may be designated as “xx” in onefigure, by “1xx” in another figure, by “2xx” in another figure, and soon. It is noted that, according to common practice, the various featuresof the drawing are not to scale, and the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034]FIGS. 1A, 1B and 1C are examples of signatures that may becaptured and digitized and/or reproduced from a digitized signature.Signature 10, illustrated as a signature image reproduced from adigitized signature record, has various unique biometric characteristicsthat render it a reliable and accurate biometric that is substantiallyunique to the person who signs it and so is reliable and accurate forcomparison to another digitized signature for authentication.

[0035] As used herein, capture of a digitized signature generallyinvolves generating or producing a digital or digitized representationof a signature made by a person. Signature capture is typicallyaccomplished by the person signing his signature on a pressure-sensitiveor position sensitive surface, such as an electronic pad o device, witha stylus or pen that may be a standard stylus or pen or a stylus or penspecially adapted for use with the electronic pad. Electrical signalsproduced by such devices are coded to produce the digitizedrepresentation of the signature.

[0036] Suitable signature sensing devices include, but are not limitedto, pressure-based touch screen devices such as computers, e.g.,computers utilizing a Windows (Microsoft), a MacIntosh (Apple) or a Unixoperating system, as well as “Palmtop” or other personal digitalassistant devices, pocket PCs and the like, using the Windows CE or Palmoperating system software, as well as pressure and induction-basedelectronic pads that function like or in place of a conventionalcomputer mouse. Examples include Wizard Brush, WP3325U and WP4030Udevices available from UC-Logic Technology Corporation located inTaiwan, Pen Power devices available from Pen Power Technology, Ltd.located in Taiwan, E-Pen devices available from InMotion located atDallas, Tex., Smart Tablet devices available from Glacier Computerlocated in New Hampshire, and similar devices available from Fujitsu ofJapan, from Hewlett Packard (HP) located at Palo Alto, Calif. and fromothers.

[0037] Authentication or verification generally comprises comparing twodigitized signature representations to determine the degree of samenessand/or similarity, e.g., for determining whether the person who signs asignature is the same person or is a different person than the person heclaims to be, i.e. the person who signed an original (or reference)signature. The biometric characteristics of a signature, e.g., such asthe total number and sequence of strokes, the slopes of various portionsof the signature, and/or the speed of pen movement at various parts ofthe signature, and/or other characteristics, are different for eachperson. Typically, one digitized signature is referred to or designatedas a “standard” or “reference” or “exemplar” signature and the other asa “transaction” or “working” signature. In practice there is nodifference between the method by which each is captured and recorded ina signature record and the apparatus employed therefor, other than thedesignation applied to the resulting digitized signature data record.Typically, a standard or reference digitized signature is captured at aregistration, an enrollment, a sign on, an initial or preliminarytransaction or other process in advance of a transaction employing adigitized signature and is stored for use in authenticating a futuretransaction. Verification and authentication are used interchangeablyherein.

[0038] Identification, on the other hand, generally comprises comparingan unknown (transaction) digitized signature representation to aplurality of known digitized signature representations to determinewhether any of the known digitized signature representations matches theunknown digitized signature representation with a sufficient degree ofsameness and/or similarity, e.g., for determining the identity of theperson who signs the unknown signature from the known identity of theperson who signed a matching known (or reference) signature. Typically,the plural known digitized signature representations are stored in acomputer database and are related to corresponding records, typically inthe same data base, pertaining to the signer thereof.

[0039] For a conventional written signature, the difference between theoriginal and a copy is often quite apparent. Such is not necessarily thecase for a conventional digitized signature. For a conventionaldigitized signature which is based upon an image of the signature oraverages of various signature parameters, cut and paste copying canresult in unauthorized application of the digitized signature. Even anexpert forger, while he may be capable of reproducing a facsimile of awritten signature that will not easily be detected as a forgery byconventional examination, will not be able to avoid detection wheredigitized signatures as described herein are compared.

[0040] In a typical signature of FIG. 1A, for example, the signature 10has a starting point 12 and comprises many strokes, each of which has adifferent slope or tangents 14. In addition, there are breaks 15 wherethe pen is lifted between strokes. Because signature 10 is a signaturereproduced from a digitized signature, the speed of pen movement isevident. Portions of the signature wherein the pen moves slowly 16 areevidenced by a series of very short segments comprising the stroke,whereas portions thereof wherein the pen moves rapidly 18 are indicatedby relatively long segments comprising the stroke.

[0041] The signature of FIG. 1B is quite different, and yet it ischaracterized by a start point 12, strokes of various slopes or tangents14, and portions of slow pen movement 16 and of rapid pen movement 18,all very different and distinctive from the characteristics of thesignature 10 of FIG. 1A.

[0042] Even the signature 10 made by the authentic person will varydepending upon circumstances: whether the person is sitting or standingor in another position, the relative position and stability of thewriting surface upon which the signature is made, the pen used, aging,lighting conditions, the environment and many other factors. Thus, theauthentic person's signature may vary significantly in size, in theslope or tilt relative to the start point 12, the actual speed of penmovement, and the like. FIG. 1C illustrates an authentic signature 10′made by the same person who made signature 10, but signature 10′ hasdifferent size and tilt. Accordingly, it is desirable that the digitizedsignature be normalized so that such apparent differences betweenauthentic signatures 10, 10′ have a less significant effect upon thecomparison of those signatures. With normalization, differences ofsignature size and tilt which tend to more reflect the circumstances,rather than the authenticity of the signature, are removed. Even withnormalization, however, it is noted that the number and sequence ofstrokes, and the slopes of the various portions and the speed of penmovement at which they are made will tend to be consistent.

[0043] As described below, digitized signatures according to the methodare not images of the signature, but may be converted into an imageformat for reproducing a representation of the original signature thatwas digitized. Such image representation may be in any suitable format,such as TIFF, JPEG, BITMAP and the like, however, in such format theimage typically requires about 3-10 kilobytes in contrast to the typical300 bytes required in the present digitized signature format. Becausesuch conversion to an image format usually produces visible segmentationof the strokes, although such is not necessarily present, the reproducedimage may be easier to detect if it were to be copied into anotherdocument or file.

[0044]FIG. 2 is a schematic flow diagram representing the generating ofa data record 40 including a digitized signature 10. A typicalapplication where the generation of a digitized signature and thecomparison of digitized signatures for authentication and verificationis useful is for transactions conducted over the Internet. Suchtransaction may include, for example, purchases made by a person at ahome or office computer connecting to the via the Internet to the website of a provider of goods and/or services and then purchasing orcontracting for goods and/or services, charging the cost thereof to anaccount with the provider, or to a credit or debit card, or to anotheraccount with a third party. Such transactions could encompass highlysensitive transactions, such as persons making banking, investmentand/or other financially significant transactions, and/or business andcommercial transactions or contracts involving many thousands ormillions of dollars.

[0045] In addition to the generation of a digitized signature thatresponds to the unique biometric characteristics of the person makingthe signature, it may be desirable to have an additional uniquenessassociated with the digitized signature to render it more difficult tocopy, or at least to make detection of such copying more easilydetected. The method of FIG. 2 generates a digitized signature 10, as isdescribed in detail herein below. A date/time tag 20 is associated withdigitized signature 10 wherein the date includes day, month and year,and the time includes the hour, minute, second, and preferably themillisecond or finer time interval. Because it is usually relativelyeasy for a computer literate person to change the date and time recordof a typical computer and so to falsify any desired date and time, thelocal computer date and time is generally to be avoided. Date/time tag20 acquires the date and time data from the Internet server throughwhich the person conducting the transaction is connected to the web siteof the other party, which date and time (e.g., to the millisecond)cannot be changed even if the person were to have access to the server.

[0046] This is thought to make it more difficult to electronically copyor duplicate or forge a digitized signature. For example, if anunauthorized use of the digitized signature is attempted by cutting andpasting an authentic digitized signature record to another document ortransaction, then the date/time data associated with the digitizedsignature from its original and authentic use will differ from thedate/time data relating to the second or further use associated when thedigitized signature record is transmitted via an Internet server. Inaddition to a signature being unique to an individual, each signaturesigned by that individual differs in some respect from other signaturessigned by him, and so will not be a perfect match when digitized andcompared. A copied digitized signature will be a perfect reproduction ofthe prior (copied) signature and so will match perfectly, therebyindicating copying. Further indicators of re-use of a digitizedsignature are discussed below.

[0047] Optionally, or alternatively or additionally, one or morehardware identifiers 30, i.e. data representative of the identity of thehardware (e.g., the computer and/or processor and/or hard drive and/ornetwork card serial numbers or other identifier) being utilized, canalso be associated with the signature record 40, thereby to provide agreater degree and ease of traceability for a digitized signatureutilized in a transaction. Also, signature record 40 including thedigitized signature 10, the date/time stamp, and the optional hardwareidentifier 30, may be encrypted by any suitable means to further securethe embedded digitized signature record against unauthorized extractionof the digitized signature, or other tampering and/or other unauthorizedreview or use.

[0048] A digitized signature record 40, such as is illustrated in theschematic diagram of FIG. 3, represents an example of a data word 40representing a digitized signature record produced according to FIG. 2.Signature record 40 includes at least three parts: digitized signature10, date/time data 20, and a relational check code 42. Relational checkcode 42 is generated, for example, from the data values of digitizedsignature 10 as illustrated by the bracket 48 and arrow therefrom tocheck code 42, or from the data values of digitized signature 10 anddate/time data 20 as illustrated by the bracket 46 and arrow therefromto check code 42, and so is indicative of those data values.

[0049] Relational check code 42 enables a recipient of signature record40 to authenticate the values of digitized signature and date/time stamp20 by independently generating a relational check code value therefromand then comparing the relational check code generated by the recipientwith the relational check code included in signature record 40. If noneof the data of record 40 has changed, whether by alteration, by actualor attempted forgery, or by transmission error, or otherwise, then therecipient-generated check code will be the same as the check code 42 ofdata record 40. If the check codes are not the same, then the integrityof data record 40 is suspect. Herein, the relational check code ornumber is usually referred to simply as the relational check code toinclude numbers and/or codes.

[0050] Where the optional hardware identifier(s) 30 is(are) utilized,relational check code 42 is generated, for example, from the data valuesof digitized signature 10 and date/time data 20 and hardwareidentifier(s) 30, as illustrated by the bracket 44 and arrow therefromto check code 42, and so is indicative of those data values.

[0051] The foregoing arrangement permits detection of errors and/orchanges to the digitized signature record at any time by reading thedigitized signature record and recalculating the relational check codewhich is then compared to the relational check code read from thedigitized signature record. If the read and calculated relational checkcodes match, then there is a high degree of certainty that the digitizedsignature record has not been changed and does not include errors.

[0052] It is noted that while the relational check code is referred toas a “code” or as a “number,” it may include numerical, alphabetic,alpha-numeric and other characters and symbols, conventional orarbitrary, as may be desired. The relational check code isrepresentative of the information stored in the digitized signaturerecord in accordance with a predetermined formula or algorithm or otherscheme, either on a character by character basis or on the basis of oneor more combinations of the characters or values stored in the digitizedsignature record. Suitable formula and algorithms include, for example,parity checks or other parity representations, sum checks, fieldrelationship checks or any other predetermined relationship between thedigitized signature record data values and the relational check code.

[0053] Thus, any change to the digitized signature record information,including a change that changes the value of the relational check codeor number, will be detectable and an indication that the digitizedsignature record contains one or more errors or changes. Typically, theparticular formula or algorithm that generates the relational check codeis not known to third parties and is not derivable from the data storedin the digitized signature record, and so the relational check codeprovides a degree of security for the digitized signature, date/timestamp, and/or hardware identifier information stored in the digitizedsignature record. The relational check code can include many bits and socan be constructed to permit error correction as well as errordetection.

[0054] The formula or other algorithm or other encoder for generatingthe relational check code or number may be provided in protectedfirmware, in software or in a combination of firmware and software, toprovide a higher level of security against deciphering or unauthorizedcoding. For additional security, each encoder may also include a uniquehardware identifier that must be paired with coding software having thesame unique identifier for enabling proper functioning. The uniqueencoder identifier may also be included in or as part of the digitizedsignature record. Further security is provided by encrypting thedigitized signature record, e.g., as by the MD5 message encryptionprotocol or other conventional 128-bit encryption in common use forInternet communication.

[0055]FIG. 4 is a schematic flow diagram illustrating a method 100 forgenerating a digitized signature and for verifying same in relation to atransaction, e.g., an Internet or other e-commerce transaction. Inmethod 100, a digitized signature is generated 110 or “captured” for aparticular user, is then transmitted 120 as digitized signature andother data in a digitized signature record or file and stored 124 as a“standard” or “baseline” or “exemplar” signature for that particularuser. Thus far, the process could be characterized as a registration orsign-up of a particular user. In practice, typically, many users wouldbe registered over a period of time. Subsequently, the user may engagein a transaction 130 or plural transactions wherein a digitizedsignature for each present transaction is verified by comparison to thestandard digitized signature previously stored.

[0056] Registration 110 comprises a user accessing 112 via a computerassociated with a device having signature capturing capability theparticular web site or Internet application. Various devices, bothstationary and mobile, may be employed for capturing a signature,including, but not limited to, touch screen devices, resistive and/orinductive and/or other pressure sensitive pads, pocket PCs, Palmtop andother hand-held devices, personal data assistant (PDA) devices, “Tablet”PCs, and the like. The stylus and/or pen associated with such device maybe a common pen (e.g., an ink-based writing device) or may be a specificdevice intended for use with the particular signature capture device,and may include an ink-based writing capability. In general, many peopleprefer an electronic signature pad that provides at the tip of thestylus or pen an instantaneous visual representation (visual feedback)of what has been written (as does an ink pen), rather than one wherethere is no visual feedback and/or the signature appears on a displayremote from the pen tip.

[0057] In accessing 112 the application, a digitized signature capturingsoftware application may be downloaded to the user's computer from theweb site via the Internet or an Intranet, e.g., as a “plug in,” if notalready present on the user's computer. The user then enters 114 hissignature and any other information or data required or desired inrelation to registration 110. Upon completion of entering 114 data, theuser confirms 116 the data and initiates transmission thereof. Inpreparing the data and signature for transmission, the signaturecapturing application encodes 118 the signature and any other data to betransmitted and protects it with a relational check code 118 asdescribed. Such information, data and signature may be entered on a“document” presented visually on the display of the user's computer, andthe entire document, as well as the signature and data, may be digitizedand protected 118 by the relational check code.

[0058] Registration 110 may include applying for a credit card or otheraccount, to supplement an existing card or account with digitizedsignature data, to register to vote, to vote by absentee ballot, toapply for insurance, to submit claims, or any other form of business,commercial or government transaction. Where digitized signature isutilized in conjunction with a credit or debit or other accountassociated with a smart card, the digitized signature may be stored inthe memory of the smart card for comparison/verification at a point ofuse.

[0059] Transmission 120 of the digitized signature and data as adigitized signature record is typically via the Internet or over anIntranet or other communication link and/or network, typically with asuitable level of encryption, such as a conventional 128-bit or greaterencryption algorithm. Date/time data (e.g., to millisecond of time)obtained from the Internet or other server is associated with thedigitized signature record and may also represented in the relationalcheck code. The digitized signature data is separated 122 from thedate/time data and each is stored 124 as a “standard” for the particularregistered user. While certain conventional signature verificationsystems require that plural samples of a person's signature be capturedin order to generate sufficient samples to statistically characterizethe signature to account for variations present in any single signature,it is not necessary with the present system to capture plural samplesalthough plural digitized signature samples may be used.

[0060] In a transaction 130, transaction 130 is initiated 132 using acomputer having an associated signature pad, similarly to that forregistration 110 above. After entering data 132 to define the desiredtransaction, the user enters 134 his signature via the signature pad andinitiates transmission 136 of the digitized signature and transactiondata to the other party, e.g., as described above. The digitizedsignature and transaction data is generated and transmitted 140 as adata and signature file, similarly to a digitized signature record, witha relational check code. Upon receipt by the other party, the digitizedsignature and date/time data are separated 144 from the othertransaction data. In addition, the “standard” digitized signature forthe person identified in the transmitted transaction data is retrieved142 and the digitized signature data for the particular transaction iscompared 146 directly therewith.

[0061] If the transaction digitized signature and the standard digitizedsignature for the person match (to within specified criteria, asdescribed below), then the transaction is confirmed 148 back to theuser. If the transaction digitized signature and the standard digitizedsignature for the person do not match, then the transaction is denied148 and the user is so advised. If permitted by the transaction protocolestablished by the party, usually the credit agency, vendor, bank,insurance company, or government agency, the user may be permitted tomake more than one attempt at entering a signature for establishing amatch or his identity may then be confirmed by other means, e.g.,personal appearance, photo identification, and the like.

[0062] It is noted that user access in method 100 may include featurespermitting access 113 by people with certain impairments and/orlimitations, such as visual impairment, hearing impairment, and thelike. For example, impaired user access 113 may include voice or otheraudible instructions and/or voice/speech recognition and/or an enlargedvisual display, e.g., line by line enlargement, to assist a sighted useror enable a visually impaired user. Physical features such as a distinctarea for signing, raised and/or textured keys on a standard or Braillekeyboard, Braille instructions, a Braille readout device, and the like,may also be utilized. Another helpful feature is audible confirmation ofdata entered, e.g., read back thereof, and the method steps, forenabling easier and timely correction of errors. Any specialinstructions or requirements for sighted users, e.g., that appear on ascreen or other display, may also be assigned to particular keys on akeyboard or given voice commands for other users. Commercial devicesand/or software for providing certain features for access by theimpaired are available from various sources.

[0063] Desirable features for conducting registration and/ortransactions as described include one or more of the following:

[0064] 1. The signature data and application program should not acceptgraphical signature representations or the like that can be copied,e.g., by cut and paste, from another source.

[0065] 2. Signature data should be captured substantially in “real time”with a reliable date/time stamp made part of the signature record alongwith the digitized signature.

[0066] 3. Devices suitable as signature pads for capturing a signatureshould be able to detect the locus and speed of the signature needed fordigitization.

[0067] 4. The signature digitizing arrangement should be in modular formthat can be attached to or associated with web-based and/or web-enabledapplications, e.g., as a software program, that can be downloadedseamlessly (e.g., without significant separate action being required onthe part of the user) when the user accesses the application, e.g., viathe Internet.

[0068] 5. The digitized signature and other data or document(s)associated with a registration and/or transaction should be protected bya relational check code generated from the data values of such digitizedsignature, and preferably also the data and/or document(s). Preferably,the relational check code is generated immediately when the userinitiates transmission of data, and the digitized signature data recordand the data and/or document file may be “wrapped” into a single file.

[0069] 6. The digitized signature should be encrypted when transmittedover the Internet, e.g., utilizing 128-bit or greater encryption coding.

[0070] It is noted that any one or more of the foregoing advantages neednot be present or produced in an embodiment including and/or utilizingthe invention.

[0071]FIG. 5 is a schematic flow diagram illustrating a method 200 forgenerating a digitized signature and for verifying same in relation to atransaction, i.e. an Internet or other e-commerce transaction. In method200, a user logs on 210 to a web-based application from his Internetbrowser and chooses 214 the specific applications of interest on anelectronic signature enabled web site, i.e. an application and web sitethat provide for generation and/or verification of digitized signaturesas described herein. It is noted that impaired access features 212 suchas sequential display of enlarged instructions, e.g., line by lineenlargement, voice instruction, voice assistance, voice recognition,tactile and/or Braille input and outputs, aural confirmation of dataand/or transaction, and/or appropriate function keys adapted for accessby the impaired, may be provided.

[0072] If the necessary drivers, signature digitization and coding,files, and/or other software is not present on the user's computer, suchmay be downloaded 218 as needed from or with the particulardigitized-signature enabled application. Download 218 may be automaticin that it is initiated by the application without user intervention orrequest, or it may require some user action, e.g., click on a “download”or “accept” button. The user may then perform 216 the operation ortransaction as appropriate, e.g., completing forms, making purchases,submitting claims, registering, and so forth.

[0073] When the user has completed entering data and otherwise enteredwhat is required for the desired transaction, he clicks 220 on the“sign” button or command to begin generation of the digitized signature.If the user has not completed the prerequisites to signing, he isreminded to provide missing data or perform omitted steps. The remindertypically is automatic in that no user action is necessary, and may takethe form of highlighting or otherwise visually distinguishing the datato be provided or the step(s) to be taken. If and when the usercompletes the necessary data and steps, the signature capture device,e.g., signature pad, is enabled for the user to enter his signature bysigning 220 thereon. The user then may submit 230 the application ortransaction with the digitized signature embedded in a digitizedsignature record associated therewith, i.e the user submits atransaction request to the proprietor of the web site subject toverification and acceptance thereof. As above, transmission of data ispreferably encrypted with 128-bit or greater encryption.

[0074] The web-based application on the server of the web siteproprietor (e.g., the server of a bank, insurance company, vendor ofgoods or service, government or private entity, and the like), verifies232 the digitized signature, Verifying 232 includes retrieving anoriginal or standard digitized signature associated with the user, i.e.the user as identified in the transaction request, from its database andcomparing that standard digitized signature to the digitized signaturesubmitted as part of the proposed transaction request. Approval 234 ofthe transaction depends upon verification 232 of the digitizedsignatures.

[0075] If the digitized signatures match to the established degree oflikeness, the transaction is approved 240 and is acknowledged 242 bytransmitting to the user a message so indicating as well as anidentifier unique to the transaction, sometimes called a confirmationcode or confirmation number or transaction number. The number or codemay include a system serial or sequence number, date/time data, and/orother data either related or unrelated to the transaction, as desired.

[0076] Closely associated with the approval/acknowledgment steps is theencoding and storing 244 of the digitized signature, date and time data(e.g., to the millisecond) from the Internet server or web site server,and transaction data, for creating a file record that may be used forverifying the authenticity of the transaction. Preferably such filerecord “binds” the data into a single record that is encrypted and/orprotected by a relational check code as described above. At least thedigitized signature for the transaction and the Internet transmissiondate/time data are related and protected by a relational check code toprovide a unique signature record (or stamp) for later use forauthentication, if needed. Optionally, all or any desired part of thetransaction data may be combined and encrypted and/or protected.

[0077] For certain applications it may also be desired or necessary tohave a written record of the transaction, as is the case where thetransaction involves voter registration and the applicable law requiresa written (ink) signature. In such instances a tangible transactionrecord is provided 246, such as by a printer either at the user'scomputer or at the web site proprietor, for ink signature by the user,and possibly with verification of identity by conventional means such asbirth certificate, driver's license, passport, photo identification, andthe like.

[0078] If the signatures do not match to the established degree oflikeness, the transaction is not approved 250 and such result isacknowledged by transmitting to the user a message so indicating.Typically, the user is requested to sign again 252 so that anotherattempt can be made to complete the proposed transaction (it is usuallythe desire of both parties that the transaction be completed). After apredetermined number of attempts wherein a matching of digitizedsignatures is not successful, the user may be “locked out” 256 orotherwise prevented from attempting the proposed and/or othertransactions, either for a predetermined period of time or permanently,as determined by the web site proprietor.

[0079] Whether the transaction is approved 240 or is not approved 250,an audit trail is generated 254 so that each transaction, proposed orcompleted can later be investigated, verified or otherwise reviewed.Typically, generating 256 an audit trail keeps track of failed attemptsto complete a transaction and locks out 256 the user.

[0080] For Internet or web-based applications, it is desirable that thesignature pads, PDAs and other devices utilized for capturing asignature be transportable and/or mobile, unlike client-server-basedapplications where a signature device is associated with each clientcomputer or where the appropriate software drives is installed on eachclient computer so that a signature device may be utilized therewith.But each computer logging on to a web site cannot be expected to havethe necessary software drivers installed. Thus, the signature deviceshould be compatible with the Internet browsers commonly utilized inaccessing the Internet, as may be provided by operating systems such asDot-NET available from Microsoft Corporation of Redmond, Wash., or by an“Active X Control” created in the Visual C⁺⁺ language for embedding inthe web-based application and/or system.

[0081] The driver for the applicable signature digitizing device and/orany needed signature digitizing software are made to be downloadedseamlessly (e.g., without requiring the user to initiate an action or tobe aware that an action is being taken automatically) to the userscomputer when the user accesses the web site application utilizingdigitized signature generation, capturing, and/or authentication. Thedriver and/or signature digitizing software preferably does not leavethe digitized signature or any signature data on the web browser or harddrive of the user or client computer when a use of the application isfinished, so as to improve security and prevent the copying of adigitized signature, although the device driver may remain.

[0082]FIG. 6 is a schematic flow diagram illustrating a method 300 forgenerating a digitized signature. The method may be referred to as“locus-based signature capture” or a “vector signature” because themethod involves characterizing the locus of the pen making the signaturefrom the start of signing to the end of signing. Among the aspectsconsidered are the size and shape of various signature elements, thenumber of strokes and/or loops comprising the signature, the order andsequence of the strokes, the tangents and/or derivatives of segments andpoints of the signature, and/or the segmental and overall speed at whichthe signature is made, and/or derivatives thereof, e.g., instantaneousspeed or acceleration. Optionally, the pen/stylus pressure of thesignature stokes may be captured if a pressure sensitive or otherpressure sensing device is utilized for signing.

[0083] In general, a device that has the ability to follow or track thestarting point and the strokes/segments of the signature should besuitable for use in practicing the invention. Information representativeof the pen/stylus speed at different segments of the strokes, the shapesand sizes of strokes, and the sequence of strokes, may typically bederived from the electronic information provided (captured) by suchdevice. In addition, if the device senses pen/stylus pressure, thepen/stylus pressure for each segment or stroke may also be obtained andincluded in the digitized signature.

[0084] In a preferred embodiment, two bytes are utilized to representthe starting point of each pen stroke and each subsequent point ismapped in relation to the immediately previous point and is coded in anumber of bits determined from characteristics of the particularsignature. Point location information is acquired and stored essentiallyin real time, i.e. as the signature is signed, in the x, y or othercoordinates of the signing surface of the signature data capturingdevice. When signing is completed, the point location data is convertedfrom the x, y or other coordinate format to locus signature format asdescribed below, and each point is typically represented in less thanone byte, e.g., for signing speeds in the normal range. However, if thespeed of signing is higher so that the number of bits required to defineeach point may exceed one byte, more than one byte may be utilized, sothat the length of coding may be self adjusting to signing speed withouthaving many unutilized bits.

[0085] In tests involving many different signatures, about 98% of thepoints required only one byte or less, and none required more than onebyte. More than about 90% of the test signatures required about 100-300bytes for the digitized signature and almost none required more than 400bytes.

[0086] In an alternative embodiment, two bytes are utilized to representthe starting point of each pen stroke and each subsequent point ismapped in relation to the previous point of the stroke and each point isthen coded into one byte, a fixed length coding. As above, pointlocation information is acquired and stored essentially in real time,i.e. as the signature is signed, and is converted to locus signatureformat when signing is completed. Each point is represented in one bytefor and signing speed. Because the preferred and alternative embodimentsare similar except for the number of bits utilized for defining eachpoint of the signature, the description of the preferred embodiment willbe sufficient to describe the alternative to one of ordinary skill.

[0087] While the difference between 300 bytes for a digitized signatureand 3000 bytes for a conventional digital signature may not seemsignificant, it becomes so when databases include large numbers of,e.g., 10 million to 100 million, digitized signatures. For example, 300gigabytes of storage capacity is required to store only one million3000-byte digitized signatures, which would require hundreds of CD-ROMsjust to store the data and would require substantial time to transmitvia a typical network. The number of voters in many of the states of theUnited States far exceed one million, as do the numbers of customers ofmany credit card companies and banks. Conventional database software,e.g., such as a Microsoft Windows-based SQL server database or an OracleUnix-based database is suitable therefor.

[0088] In terms of FIG. 6, for example, touching a Start Sign 302 buttonpreferably displayed on the signature pad device with the pen/stylusinitiates signature capture process 300 with signature capture 310,although the start button and other functional buttons may be providedon another touch-screen device or via a keyboard. Signature capture 310comprises detecting and recording the coordinates and times at which thestylus is touching the signing surface during the signing of thesignature. The coordinates and the times thereof are recorded in thecoordinate system and at sampling timing and times of the device havinga touch-sensitive signing surface as the signature is signed. Time datamay be recorded by actually storing timing data or may be indirectlyrecorded in that the time data is inherent in the sequence of stylusposition coordinate data and the sampling rate of the signing surfacedevice.

[0089] Next the captured 310 stored coordinate and time data istransformed or converted into a compact format for a locus-baseddigitized signature. Each stroke of the signature is separately codedand the digitized representation thereof is stored in a digitizedsignature data record (also sometimes referred to as digitized signaturedata and/or as a digitized signature record) in the same order in whichit was signed in the complete signature.

[0090] For each digitized signature data record, the first four bits ofthe first byte specify the number of bits that will be utilized tospecify each x coordinate of that signature (as the difference in xdistance relative to the x coordinate of the previous point) and thesecond four bits of the first byte specify the number of bits that willbe utilized to record each y coordinate of that signature (as thedifference in y distance relative to the y coordinate of the previouspoint). It is noted that the numbers of bits specified for the xcoordinate differences and for the y coordinate differences of eachstroke of a given signature may be different, however, what ever numberof bits is specified for each is maintained for the entire signaturerecord. Preferably, the respective numbers of bits assigned to code thex and y coordinate differences from those of the previous point aredetermined from the recorded actual x and y coordinates (i.e. calculatedtherefrom) recorded during signing of the signature, so that efficientutilization of the bits in the digitized signature record may obtain.

[0091] Note that the numbers of bits specified for the respective x andy coordinate differences may be different from one signature to anothersignature. For example, the x difference values may be expressed threebits and the y difference values in two bits, and so five bits arerequired to specify the location of any given point of a signature interms of the differences of its x and y coordinates from those of theprevious point. When coded in this example, the first five bits of thefirst byte define x, y coordinates of a first point, the last three bitsof the first byte and the first two bits of the second byte define thenext point, the third through seventh bits of the second byte define thenext point, and so forth. Thus, on average, each byte defines the x andy coordinates of more than one point, thereby reducing the size (numberof bytes) needed for a digitized signature record to describe aparticular signature in comparison to a coding wherein each point iscoded in one byte.

[0092] The second byte of the signature record specifies the number ofsignature points that are sampled and/or recorded per unit of time bythe signature capture device, e.g., typically up to 255 differentsampling rates can be specified in an 8-bit byte, e.g., in units ofsamples or points per second, and is useful to define the timing of anypoint relative to any other point and relative to the signature startingpoint, and is also useful when the digitized signature record isnormalized prior to comparison with another signature record and/orprior to being displayed.

[0093] The first stroke of the signature is coded beginning with itsstarting point x coordinate being specified in the third byte of thesignature record and its starting point y coordinate being specified inthe fourth byte of the signature record. The subsequent pointcoordinates of the first stroke are coded in the number bits specifiedin the first byte of the signature record and stored as the fifth andsubsequent bytes (as differences in x and y position from theimmediately preceding point) until the entire stroke is coded. The endof the stroke is indicated by an “end mark” point, e.g., in the numberof bits specifying a point wherein all of the bits are ones, i.e. theend mark has its maximum value. Alternatively, the end mark may be onebyte, and if any bits of the byte immediately preceding such end markbyte are unused in coding x and y coordinate differences, those bitpositions are set to zero.

[0094] Thus, in the fifth and subsequent bytes, each byte need notcorrespond to a particular x and/or y coordinate, but all of the bitsare utilized to specify differences of x and y coordinates of a presentsignature point from the immediately preceding signature point, so thatno bit positions are unused (except possibly in the last byterepresenting a stroke in which unused bits are set to zero).

[0095] Each subsequent stroke is coded in like manner, i.e. beginningwith two bytes specifying the x and y coordinates, respectively, of thestarting point thereof, and the specified number of bits thereafterspecifying differences of intermediate points until concluding with anend mark, all stored without unused bits in the bytes following thefirst two bytes thereof, in like manner to that described for the firststroke.

[0096] Thus, the first two bytes of a digitized signature record specifythe coding conditions for subsequent bytes, and each stroke of thesignature follows seriatim in the order signed, each stroke being codedin two bytes specifying the starting point coordinates thereof followedby a number of bytes containing bits specifying differences in thecoordinates thereof and ending in an end mark, until all of the strokesof the complete signature are coded. Each coded stroke is characterizedby two starting bytes and an end mark between which are interposed bitsspecifying the locus of the points of the signature, not necessarily inone-to-one correspondence with the bits making up particular bytes.

[0097] Because the timing of each of the points of the coded signatureis either explicitly or implicitly specified, the dynamiccharacteristics of the signature, such as stroke timing and/or speedand/or acceleration may be determined from the digitized signature datarecord, for use in comparisons for identification, verification and/orauthentication.

[0098] As a result, the digitized signature record described isanalogous to a “movie” of the signature, and contains the unique anddistinctive dynamic signing characteristics thereof, as contrasted toconventional graphic and image digital signatures which are analogous toa snapshot at one instant in time, i.e. after the complete signature issigned, and lack the unique and distinctive dynamic signingcharacteristics thereof.

[0099] Returning to describing the foregoing in terms of FIG. 6, stylusdown 312 first occurs when the signer touches the stylus to the writingsurface of the signature pad and movement of the stylus 314 is thendetected and point locations are recorded. After each point locationrecording it is determined 316 whether the stylus is up (i.e. not incontact with the writing surface) or down (i.e. in contact with thewriting surface). If stylus up 316 is negative N, then the stylus is onthe writing surface and further stylus movement 314 is recorded. Thisloop 314, 316 repeats so long as stylus up is negative N, i.e. thestylus is in contact with the signing surface.

[0100] If stylus up 316 is positive Y, the stylus has been lifted offthe writing surface indicating the end of the stroke that began atstylus down 312. Testing for ending of the signing 320 may follow one ofseveral alternative indications. Typically, end of signing is indicatedby the signer touching a suitably labeled button displayed on thesignature pad device to indicate that he has completed signing hissignature. If ending 320 is negative N, then the next stylus down 312 isawaited, and steps 312, 314, 316, 318, 320 repeat as described for eachstroke of the signature until ending 320 is indicated positive Y. Whenending 320 is positive Y, signature capture 310 is complete and thecaptured signature data may be produced 330 in a predetermined format.Alternatively and/or additionally, expiration of a predetermined timeperiod can be used to initiate ending 320 path Y so that the signaturecapture device is not tied up if the signer forgets or neglects toindicate the ending of his signing by touching the button.

[0101] Producing signature data 330 initiates the coding described abovewherein the recorded coordinates of signature points are coded asdifferences in coordinate value from a previous point, such as theimmediately preceding point, except for the starting point of the stoke.Checking the sampling speed 332 comprises determining the rate at whichthe signature capture device (signing surface) produces signature pointcoordinate values and specifying that rate in the second byte of thedigitized signature record. Calculating the needed bits 334 for eachpoint of the signature comprises determining the maximum differences ineach of the x and y coordinate values between any two contiguous sampledsignature points and specifying the number of bits needed to representsuch maximum difference. Calculating 334 is preferably performedindependently for the x coordinate values and for the y coordinatevalues.

[0102] Finally, compressed signature data is produced 336 as describedabove with each stroke of the signature specified in two initial byteslocating the starting x and y coordinates and an end mark, between whichare coded the differences between adjacent signature points in terms ofdifferences in the x and y coordinate values thereof relative to theimmediately preceding signature point. When all of the strokes have beencoded in terms defined by the parameters specified in the first twobytes of the digitized signature record for all of the sequence ofstrokes comprising the signature, method 300 ends 340.

[0103] In summary, the signature signed with a pen/stylus on a signaturepad or other device is captured with reference to the starting point(location, e.g., coordinates, in terms of, e.g., x, y coordinates) ofthe signature which is recorded and serves as the reference point forsubsequent signature data, at least in the first stroke of thesignature. The starting and ending points of each stoke of the signatureand of each point of each stroke are recorded relative to a previoussignature point as they are signed. Points (locations) along each strokeand segment of the signature, i.e. between each set of stroke startingand ending points, are recorded as they are signed and are codedrelative to a previous point. In addition, the timing of the signing ofthe points of each segment and stoke is also recorded, either expresslyor inherently in the location data, by reference to the sampling rateand/or timing.

[0104] All of the foregoing are recorded (stored) in a digitizedsignature data record in the order in which they occur, thereby toproduce in essentially real time a locus of points of the signaturerelative to the previous point of the signature, and the timing thereof.It is noted that this locus-based format of signature data lends itselfto mathematical regression, calculation of derivatives and othermathematical manipulation useful for the comparing and authenticating ofdigitized signatures.

[0105] The signature point location and timing data for each stroke of asignature acquired by method 300 render the dynamics of a signature tobe determined. E.g., speed can be determined from the distance betweenpoints and the recorded times at which the points were made andinstantaneous velocity (speed and direction) of a pen stroke may bederived from the sequences and point-to-point spacing or density of eachsegment of the signature. The tangent of the curvature of a strokeand/or of a segments thereof can be derived from the point locationdata. Acceleration at any point of a signature may be derived fromvelocity, if desired. Such characteristics are typically determined bycalculating slopes, by regression analysis, and the like.

[0106] The timing of the recording of point locations is set atpredetermined rates by the processor and controlling software, e.g., ata rate in the range of about 40 to about 120 samples per second. Thisrate is typically determined by the sampling rate of the signature paddevice in combination with the processor or at any desired lower rate,and typically is lower for PDAs and other portable devices.

[0107] Preferably, the stored signature coordinate and time datacontained in a digitized signature data record is normalized in size andtime step length prior to comparison os signature data foridentification and/or verification and/or authentication. Normalizationmay utilize conventional scaling, interpolation and regression methods,thereby to reduce, if not remove, differences that may be caused by theparticular equipment utilized to capture the signature and/or theconditions under which the signature was signed.

[0108] Dynamic characteristics of the signature comprise at least thefollowing, although less than all characteristics are utilized in atypical signature comparison:

[0109] “s” represents the size and shape of the entire signature.

[0110] “n” represents the number of strokes in the signature.

[0111] “o” represents the order or sequence of strokes of the signature.

[0112] “l” represents the number of closed loops of the signature.

[0113] “d” represents the distance or length of strokes of thesignature.

[0114] “t” represents tangents and derivatives of segments and/or pointsof the signature.

[0115] “v” represents the velocity or speed of segments and/or an entiresignature, and derivatives thereof.

[0116] “p” represents the pressure applied in making the strokes of thesignature, if a pressure-sensitive signature pad is employed.

[0117] Because different computers and signature capture devices willcapture and map signature points at different densities and ratesdepending, for example, on resolution and/or size of the signingsurface, processor operating speed, mouse and/or signature pad samplingrate, the available RAM memory and the like, the captured signaturepoint data is preferably normalized so as to be relatively consistentirrespective of the hardware utilized in its capture. Normalizationreduces the effects of differences in the raw signature point data,e.g., the x, y coordinate data, with respect to timing and/or thedimensions of the signing surface and its resolution.

[0118] Commonly available personal computers typically perform thecapture and generation of digitized signature data, i.e. in the locusbased signature format described, in one second or less (excludingsigning time) and can make the comparison for authentication in shortertimes, e.g., within milliseconds, and can rapidly transmit same via theInternet.

[0119] Normalization to any convenient common or “standard” hardwareplatform is suitable, for example, a Pentium® processor operating at acommon speed, such as 233 MHZ or 850 MHZ or the like, and can be basedon capturing the speed of the simulation of the mouse device utilizedwith a particular hardware platform at some time during the signing andsignature digitization. (Digital signature pads are often interfacedwith the processor in the same or in a similar manner to that of themouse device.) Normalization facilitates comparison and authenticationof digitized signatures captured and generated on different hardwareplatforms, whether connected directly, by a network, or via the Internetor an Intranet, or other network. As hardware having greater operatingspeed and/or greater data capability, e.g., a 64-bit processor, becomeavailable, the normalization can be adapted thereto as desired and/or asneeded. Normalization does not significantly alter the unique anddistinguishing dynamic characteristics of a given person's signature,but is believed to tend to reduce the effects of size and hardware onthe unique and distinguishing characteristics of the signature.

[0120]FIG. 7 is a schematic flow diagram illustrating a method 400 forcomparing and/or authenticating a locus based digitized signature. Areference digitized signature data record is obtained 410 and thedynamic characteristics (s, n, o, l, d, t, v, p, . . . ) thereof arederived 412 therefrom. Similarly, a digitized signature data record forthe present transaction is obtained 414 and the dynamic characteristics(s, n, o, l, d, t, v, p, . . . ) thereof are derived 416 therefrom. Eachsignature will have a unique set of signature characteristic values thatcan be compared to the set of characteristic values of another signatureto determine whether the two signatures are likely to have been made bythe same person.

[0121] In making such comparison, a ratio of each respectivecharacteristic value of the two signatures is derived 420, wherein valueratios S=s₁/s₂, N=n₁/n₂, O=o₁/o₂, and so forth, with the smaller valuebeing the numerator and the larger value being the denominator so thateach ratio is unity or less. It is noted that each ratio will be closerto unity as the similarity of that characteristic of the two signaturesincreases, i.e. where the two signatures are closer to being the same,and will be lesser in value as the similarity of that characteristic ofthe two signatures diminishes, i.e. the two signatures are moredissimilar.

[0122] The probability P_(S) that two signatures are the same isdetermined 430, wherein the probability P_(S) can be represented by theproduct expression:

P _(S) =S ^(á) N ^(â) O ^(÷) L ^(ã) D ^(ë) T ^(ä) V ^(å) P ^(ö)

[0123] wherein á, â, ÷, ã, ë, ä, å, and ö are weighting factors for eachof the characteristic value ratios S, N, O, L, D, T, V and P,respectively. Greater weight is accorded to any given value ratio bymaking its weighting factor greater than unity. For example, where thespeed value ratio S and the tangent value ratio T are deemed of greaterimportance as indicators discriminating an authentic signature from abogus, forged or other non-authentic signature, their respectiveweighting factors á and ä may be increased to a value as high as two orthree. If two signatures are exactly identical (practically animpossibility except for an electronic copy), then each ratio S, N, O,L, D, T, V and P will be unity and P_(S)=1. If two signatures arecompletely dissimilar, then each ratio S, N, O, L, D, T, V and P willbecome small (approaching zero) and P_(S) will approach zero.

[0124] Authenticating a signature comprises comparing the characteristicvalues thereof to the characteristic values of an exemplar or standardor reference digitized signature record (or any previous digitizedsignature data) using the foregoing ratios to produce a P_(S) for thetwo signatures being the same. Specifically, the probability P_(S) valueis compared 432 to a predetermined range of values deemed indicative ofauthenticity. If the probability P_(S) is within the predeterminedrange, then comparison 432 is positive and the yes Y result obtainswherein an indication of authenticity is provided 434. If theprobability P_(S) is not within the predetermined range, then comparison432 result is negative and the no N result obtains wherein an indicationof non-authenticity is provided 436.

[0125] Typically, the value of P_(S) required for indicatingauthenticity is about 0.5 (about 50% relative match) or greater,however, a value of P_(S) that is too high 444 indicates a probabilitythat the signature has been copied or produced electronically 446, i.e.is not signed by the same person. Thus, values of P_(S) indicatingauthenticity are usually a range, for example, a range of 0.45 to 0.75(45-75% relative match) has been found satisfactory for one applicationto voter registration. Values of P_(S) less than about 0.30 (about 30%relative match) are likely to indicate a forgery and values of P_(S)greater than 0.8 (about 80-100% relative match) are most likely toindicate an electronic forgery. For signatures with values of P_(S) inthe range of 0.30-0.45 (about 30-45% relative match), the signer may berequested to again sign his signature for one or more additional triesfor verification and/or authentication. Examples of values of P_(S) thatmay be utilized as thresholds indicative of authenticity include valuesof about 0.45, about 0.5, about 0.6, about 0.7, about 0.75 and about0.8, and examples of values thereof that may be utilized as thresholdsindicative of dissimilarity include values of about 0.45, about 0.4,about 0.3, about 0.25 and about 0.2.

[0126] Where it is desired to indicate or display to an authenticator orverifier or to another person the results of the authenticationcomparison, such as the percent relative match, it may be desirable toadjust the calculated value of P_(S) so that a standardized range ofvalues are presented. Such adjustment or transformation from thecalculated values of P_(S) to the displayed values of P_(S) may beproportional or not, and/or may be linear or non-linear, and may beimplemented, e.g., by multiplication by a scaling factor or a factorobtained by table look up. Typically, the threshold values and rangesare determined on a sliding scale depending on the degree of certaintydesired for a particular authentication or identification, and areadjusted so as to be between zero and one (i.e. 0-1.0).

[0127] It is desirable to avoid authentication errors, i.e. indicationsof authenticity for two signatures signed by different persons and/orindications of lack of authenticity for two signatures signed by thesame person. Errors of the first sort tend to increase as the lowerlimit of the range for P_(S) is reduced to too low a value. Errors ofthe latter sort tend to increase as the lower limit for the range ofP_(S) is increased to too high a value or if the upper limit thereof isreduced to too low a value. As the consequences of an authenticationerror become more serious, e.g., as between a credit card transaction ofvalue less than $25 and access to a government classified facility, therange of values of P_(S) accepted as authenticating two signatures maybe both raised and narrowed. Even for transactions of the same type, therange of values of P_(S) accepted as authenticating two signatures maybe changed to more closely suit the circumstances, e.g., setting ahigher and narrower range for credit card transactions valued at over$500. than for transactions of lesser value. In fact, the range ofvalues of P_(S) accepted as authenticating two signatures may bespecifically adjusted as a function of the value of the transaction.

[0128] Evaluations have indicated that at least two different ratios ofcharacteristic values should be employed in a signature authentication,e.g., so as to provide a probability P_(S) that is meaningful indicatorof authenticity of digitized signature. For example, the factor ratios Vfor the relative speeds of the segments and/or stokes of a signature andT for the relative tangents thereof were found to be of moresignificance in discriminating between authentic signatures andnon-authentic signatures. In particular, where a signature is signed bytracing with the stylus an authentic signature placed on the signingsurface of the signature pad device, the derivatives of speed ratio V(or acceleration characteristics) are significant in distinguishingauthentic and non-authentic signatures. A combination of both theacceleration and the instantaneous speed of the stylus at one or moreparticular segments of a signature tends to provide distinctiveness tothe signature as signed by a particular person, and so while requiringmore mathematical manipulation, may be advantageously utilized inauthenticating a signature, e.g., as in a more important utilization ofdigitized signature authentication.

[0129] In another example, the factor ratios S for shape and size and Tfor tangents were found to be of more significance in discriminatingbetween authentic signatures and non-authentic signatures, although suchmay not always be the case and may not be the case for signatures usingnon-English alphabet characters.

[0130] It is noted that the foregoing authentication may be useful isdetecting signatures made by the same person using other than theperson's true name. Because the alias may be used less frequently,especially for signed transactions, there may be a lesser value forP_(S) produced 440 for the alias signature than for a true namesignature, and monitoring for values of P_(S) slightly below the lowerlimit of the range for authentication may facilitate detection 442 ofsuch signing of aliases. For example, where the range of P_(S) fordigitized signature authentication is 0.45-0.80, the range of P_(S) forinvestigating possible alias use may be 0.0-0.3, on the same relativescale. An example of this sort of circumstance may be where a personseeks to vote plural times using his true name and one or more aliases,or where the person is a practiced forger of a signature. Digitizedsignatures based upon the dynamic characteristics of the signature canbe more discriminating than are image-based signatures which may lookalike after the fact, but are very different dynamically when signed.

[0131] It is further noted that a digitized signature according to theinvention includes the dynamic biometric information of the personsigning and so, because the essential information is stored in thedigitized signature data record, the factors considered and theweighting applied thereto in comparing and/or authenticating suchdigitized signature may be changed and/or improved even after thesignature is captured and the digitized signature data record generated.For example, if it is later desired to improve the verification processby considering different and/or additional characteristics, such as theacceleration of the pen strokes, the verification/authentication processcan be changed and the pre-existing digitized signature data may beutilized therewith, i.e. there is no need to secure a new signature forsuch comparison. Such is not the case for prior art digitized signatureschemes which are based on averaged or statistical signaturecharacteristics and which are believed to require re-enrollment orre-registration in order to acquire additional signatures for comparisonin an improved authentication process.

[0132] Further, the present invention may be employed for comparingplural digitized signatures previously captured and generated to apresent signature for verification and/or authentication. In suchcomparison, it is preferred that each prior digitized signature datarecord is separately compared to the present digitized signature, andthat the results of such plural comparisons be utilized according to apredetermined protocol for determining authenticity or the lack thereof.For example, because a person's signature may change over time, e.g.,due to aging, illness, physical changes and the like, comparisons tomore recent known authentic digitized signature data records for thatperson may be given greater weight in the authentication protocol. Suchprotocol may require that all or less than all comparisons produce aP_(S) within a range of values indicative of authenticity, and the rangeof values of P_(S) deemed authentic may differ for more recent and lessrecent digitized signature data.

[0133] A protocol for comparing a transaction signature to pluralstandard signatures of the same person accumulated over a period of timemay include first comparing the transaction signature with the mostrecent reference signature first, then comparing it with the second mostrecent signature, and so forth, and comparing it with the oldestreference signature last. Greater weight may be given to comparisonswith more recent reference signatures or the same weight may be given toall comparisons, however, any desired weighting protocol may beutilized. Alternatively, once an image signature in bitmap format isproduced, it may easily be translated or converted into any otherstandard format, e.g., TIFF and JPEG, by conventional means.

[0134]FIGS. 8A through 8D illustrate examples of screen displays usefulwith the digitized signature apparatus and method described. FIG. 8Aillustrates a screen display 350 including two windows 360S and 360Twherein are displayed a standard or reference signature and atransaction signature, respectively, such as would be displayed after aperson has accessed a locus-based digitized signature application andhas signed his signature in connection with a transaction. The signaturedisplayed in window 360S represents an image representation derived froma locus-based digitized signature previously captured and window 360Trepresents an image representation derived from a locus-based digitizedsignature presently captured and which is to be authenticated bycomparison to the standard locus-based digitized signature. Windows360S, 360T are identified by labels 362S, 362T, respectively. Clicking“Compare” button 364 initiates the comparison of the standard andtransaction signatures and enables the signature pad or other device forthe next transaction, e.g., alternatively clicking a “Submit” button ora “Process Transaction” button in submitting the transaction forprocessing. Clicking “Cancel” button 366 deletes the transactionsignature and enables the signature pad or other signature device forthe signer to again sign his signature. Optionally, if neither the“Compare” or the “Cancel” button is activated within a predeterminedtime, then the process may “time out” to clear or reset the signaturedevice and processor in preparation for another transaction, or maydisplay a prompt for the person to take the next action, and allow timefor him to do so, before timing out.

[0135]FIG. 8B illustrates screen display 350 after “Compare” button 364has been activated to initiate comparison of the standard locus-baseddigitized signature and the transaction locus-based digitized signaturein the case where the authentication process has determined that the twosignatures are a match, i.e. are authentic. An overlay window 370 isdisplayed to indicate that the result of authentication is a positivematch and that the transaction signature is likely signed by the sameperson who signed the standard signature. Optionally, the result of theauthentication process may be displayed, e.g., as a percentagerepresentative of the probability P_(S) determined in the authenticationprocess. An “OK” 372 is provided to remove window 370 and take the userto the next screen.

[0136]FIG. 8C illustrates screen display 350 after “Compare” button 364has been activated to initiate comparison of the standard locus-baseddigitized signature and the transaction locus-based digitized signaturein the case where the authentication process has determined that the twosignatures are not a match, i.e. are not authentic. An overlay window370A is displayed to indicate that the result of authentication isnegative and that the transaction signature is not likely signed by thesame person who signed the standard signature. Optionally, the result ofthe authentication process may be displayed, e.g., as a percentagerepresentative of the probability P_(S) determined in the authenticationprocess. An “OK” 372 is provided to remove window 370A and take the userto the next screen.

[0137]FIG. 8D illustrates screen display 350 after “Compare” button 364has been activated to initiate comparison of the standard locus-baseddigitized signature and the transaction locus-based digitized signaturein the case where the authentication process has determined aprobability P_(S) that is too low to indicate that the two signaturesare a match and is too high to indicate that the two signatures are nota match, i.e. the transaction signature may or may not be authentic. Anoverlay window 370B is displayed to indicate that the result ofauthentication is not a positive match and/or that the transactionsignature may or may not have been signed by the same person who signedthe standard signature. Optionally, window 370B may direct furtheralternative and/or additional steps for attempting to authenticate theperson's identity and complete the transaction, such as requesting thatthe person show identification (ID). The result of the authenticationprocess may or may not be displayed, e.g., as a percentagerepresentative of the probability P_(S) determined in the authenticationprocess. An “OK” 372 is provided to remove window 370B and take the userto the next screen.

[0138]FIG. 9 is a schematic flow diagram illustrating a method 500 forreproducing a digitized signature in an image or graphic format from alocus-based digitized signature data record. In an image or graphicformat, the digitized signature may be viewed by any one of many commonviewers for providing a visual representation of the digitizedsignature. This feature of the invention is advantageous in that adigitized signature captured in the locus-based format may be convertedinto a format that may easily be viewed, printed or used in aconventional application without substantial loss of shape or detail,however, the size of the digitized signature data record in thelocus-based format according to the invention is significantly smallerthan is the equivalent signature data in an image or graphic format. Theconversion to image format exemplified in method 500 may include scalingto either a larger or smaller size. In the example of FIG. 9, the imageformat is a bitmap format, i.e. a file having a “.bmp” extension,however, any desired format, e.g., the TIFF or JPEG formats, could beproduced.

[0139] Converting 502 locus-based digitized signature data to bitmap“.bmp” format initiates the reading 504 of the signed data, i.e. thelocus-based digitized signature data for use in creating bitmap data506, and ultimately to save 508 the data when transformed to bitmap dataformat as a bitmap “.bmp” file. Creating 506 bitmap data comprises arepetitive process of converting locus-based digitized signature pointsinto bitmap pixels. The method begins at a point location (x,y) andadvances through the point locations (x,y) until all are processed ortransformed into pixels in bitmap format.

[0140] For example, the initial or starting point location (x,y) of thelocus-based digitized signature is read 510 and is then determined 512whether it is the first point of a signature stroke. If the point is thefirst point of a signature stroke, a positive result Y, the pointlocation moves 514 to that point location (x,y) and two things happen:(i) the pixel is set 520 to fill the locus point data into a memoryblock in bitmap format and (ii) the point location recycles to read 510the next location (x,y) in the locus signature data. If the point is notthe first point of a signature stroke, a negative result N, two thingshappen: (i) the point indicates 518 a line from the previous pointlocation to the present point location (x,y) and (ii) the point locationrecycles to read 510 the next location (x,y) of the locus signaturedata. The line is calculated 518 on a recycling basis to define thesequence of points representing the line and the pixels thereof are set520 to fill the locus point data for the line (i.e. the sequence ofpoints) into the memory block in bitmap format

[0141] It is noted that because the locus-based digitized signature dataincludes all the point locations of the signature, only the signaturepoint locations need be processed and converted into the desired imageformat (all other locations are background), and so the conversionprocess is relatively efficient. It is also noted that while the pointlocation data of the locus-based digitized signature will reproduce anexact replica of the original signature (at least within the resolutionlimitations of the signature pad or other device utilized to capture thesignature data), once the conversion is made all of the dynamicbiometric data (e.g., the timing, speed, sequence of strokes and/orpressure) relating to the signature is lost and the locus-based digitalsignature data cannot be retrieved or derived or otherwise obtained fromthe image data.

[0142] Even if the image data were to be converted into a locus ofpoints by making certain assumptions concerning the order and sequenceof the strokes, in addition to possible errors in the assumed order ofthe strokes of the signature, the dynamic biometric data (e.g., thetiming, speed, sequence of strokes and/or pressure) is unrecoverable andan exact digitized signature cannot be derived. For example, one cannotdetermine from the image when in making the signature the letter “t” iscrossed and the letter “I” is dotted. Thus, the locus-based digitizedsignature is relatively secure because it cannot be reproduced (e.g.,forged or otherwise used without authorization) from a digital imagesignature. Typically, values of P_(S) of about 0.8 or greater usuallyindicates a signature has been electronically copied, e.g., is or shouldbe considered to be a suspected electronic forgery.

[0143] The only way one can copy the locus-based digitized signaturerecord is to intercept it while it is being transmitted from thesignature capture device to the server on which digitized signaturerecords are stored in a database, and such transmissions are preferablyencrypted and associated with Internet server time/date data. Attemptingto use such intercepted digitized signature data would produce acomparison wherein the probability value P_(S) is too high forauthentication, even if the signature data is perturbed in some way totry to avoid it being an exact copy.

[0144]FIG. 10 is a schematic block diagram of example apparatus 600 forcapturing and generating a digitized signature and for verifying same inrelation to a transaction. Example apparatus 600 is illustrated asincluding a cental computer or server 610 in which resides a database inwhich digitized signature records including locus-based digitizedsignature data are stored and preferably are indexed. Central server 610is in communication (represented by double-ended arrows) with one ormore (typically a plurality of) local computers or servers 620,typically located at sites remote from central server 610. Each of thelocal or distributed computers and servers 620 may optionally include adatabase in which digitized signature records including locus-baseddigitized signature data is stored, such as a subset of the records ofthe database of central server 610.

[0145] Each of the local or distributed computers and servers 620 is inturn in communication with one or more (typically a plurality of)computers 630, such as personal computers and/or laptop computers,typically located at sites remote from local server 620 and/or at leastapart therefrom at the same site. A signature capture device SD 365,such as a signature pad, a PDA and the like, is typically associatedwith each of computers 630 for the signing of signatures thereon toproduce in cooperation with computer 630 locus-based digitized signaturedata.

[0146] Computer 630 generates a digitized signature data record, e.g.,as described above in relation to FIG. 3, utilizing the locus-baseddigitized signature data captured by device SD 365 and computer 630, andtransmits the digitized signature record to local server 620 which inturn communicates the digitized signature record to central server 610.If the digitized signature record is new, it may be added to thedigitized signature database, and if it is a signature relating to atransaction, it my be compared to digitized signature data in suchdatabases for verification and/o authentication. A signature capturedevice 365 may likewise be associated with a local computer 620 forproducing locus-based digitized signature records therewith.

[0147] In the context of voter registration, for example, apparatus 600may be employed to register voters and/or to request and/or make changesand adjustments to voter records and information at any of the locationswhere one of computers 610, 620, 630 and an associated signature deviceSD 365 is located. Additionally and/or alternatively, computers 620and/or 630 may be voting machines or may run voting machine software soas to permit voting from such locations. In the voting context,locus-based digitized signature capture and authentication may beutilized for verification of the identity of voters and of their beingproperly registered to vote, as well as for assisting in the detectionof persons attempting to vote more than once or in the place of aregistered voter, either locally or anywhere in the jurisdictionsincluded in the databases in local (e.g., county) computers 620 and/orin the cental (e.g., state) computer 610.

[0148] In voting and/or vote registration, a printer LP 640 may beassociated with any one ore more of computers 630, 620 and/or 610 forprinting a record of information and/or a transaction conducted on suchcomputer. If required by law that registration applications and/orchanges to voter information be recorded on a paper document or otherrecord, printer 640 prints such document or record, such as a voterregistration form or a provisional or absentee ballot, which can then besigned with an original ink signature to meet the legal requirement, inaddition to the electronic record including a locus-based digitizedsignature. If a particular voter does not want to use a digitizedsignature for registration or another transaction, then the document orrecord provided by printer 640 may be signed with an original inksignature without the electronic record being signed with a digitizedsignature. In either case, the signed paper document or other record maybe submitted at the location or by mail, as appropriate.

[0149] Communication (represented by double-ended arrows) among variousones of computers 610, 620, 630 may be via any convenient communicationlink, including but not limited to, wire and cable, telephone system,optical fiber, optical transmission, radio or other RF transmission,network, LAN, WAN, an Intranet, the Internet, and the like. Eachregistration location and/or polling place thus has essentially directand immediate access to the digitized signature and other records storedin databases at higher jurisdictions, e.g., voter registration databasesat county and state levels.

[0150] Where such access is via the Internet and/or world wide web, theonly communication facility needed at any location is a conventionaltelephone line to connect to the modem of computers 620 and/or 630. Thuscomputers 630 may be computers resident at or laptop computerstransported to any desired location, such as libraries, schools, vehicleregistration and/or inspection sites, police stations, municipalfacilities, government offices, military bases, shopping centers, or anyother location where it is desired to register voters and/or conductvoting. Where a computer 630 is already in place at a location, e.g., asis common for a library, and lacks a signature device 365, only asignature device SD 365 need be transported to conduct registrationand/or voting at such location. Alternatively, a user could check out orborrow a signature pad from a library and/or government office forregistering from any computer having Internet access, e.g., at a home orat a work place

[0151] In certain applications it is relatively easy to quickly retrievethe reference or standard digitized signature from a digitized signaturedatabase because the person enters his name or an identifying numberunder which he has registered or enrolled, thereby identifying himselfrelative to his standard signature. In other applications, however, itmay be desired to compare digitized signatures without knowing theidentity of the signer, as may be the case, for example, for the systemand method described in U.S. patent application Ser. No. 10/127,787entitled “VOTING FRAUD DETECTION SYSTEM AND METHOD” filed by KevinKwong-Tai Chung on Apr. 22, 2002, which is hereby incorporated herein byreference in its entirety. The number of comparisons required before thedesired standard digitized signature data is identified and retrievedcan be come quite large and require substantial time, particularly wherethe number of records in the database is large. For example, voter andcredit card databases could have many millions of digitized signaturedata records therein.

[0152] In such instances, finding the standard or reference digitizedsignature and/or identifying the person signing a signature isfacilitated by indexing of the digitized signature data records.Indexing the digitized signature data records is typically based uponthe characteristics of the digitized signature. For indexing numericalvalues, one convenient indexing arrangement includes dividing a range ofvalues that may form a continuum into a number of bands or quantizationlevels. Typically, the bands or levels are non-overlapping and dividethe continuum in to a manageable and/or convenient number of groups orbands, e.g., a value that may range between zero and ten may bequantized into bands of 0-1, 1-2, 2-3, and so forth, or may simply berounded to the nearest integer value. Characteristics useful forproviding an index or catalog include, for example:

[0153] The number of strokes and dots in the signature (dots are strokeswhere the starting and ending points are the same or so close togetheras to essentially be a point, such as in the letters “I” and “j” or in apunctuation “period”).

[0154] The relative lengths of the strokes taken in sequence. E.g., thelength can be categorized to the nearest integer number of centimeters(for indexing, n cm±0.5 cm=n cm, where “n” is an integer), and dots areless than 0.1 cm.

[0155] The number of closed loops in each stroke. E.g., closed loops mayoccur in script letters such as “b”, “e”, “l” “o” and so forth.

[0156] The relative ratio of the length of the signature to its height.E.g., the ratio X/Y rounded to the nearest integer (1±0.5=1, 2±0.5=2, .. . ).

[0157] The total normalized length of the signature, i.e. the cumulativelength of all the stokes of the signature. This may also be categorizedto the nearest integer number of centimeters.

[0158] The relative speed of completing the signature, i.e. the totaltime the signer takes to sign his signature from initial touching of thestylus to the signature pad to the final lifting of the stylus. Time maybe categorized, for example, to the nearest whole second or two seconds.

[0159] Other characteristics of the signature, such as the derivedvalues of tangents of one or more specific segments (e.g., a midpointsof closed loops), the instantaneous speed of one or more specificsegments (e.g., midpoints of a stroke, instantaneous acceleration at aspecific segment, and the like.

[0160] For those indexing characteristics relating to size, thedimension preferred for indexing is that after the signature isnormalized for size and tilt. It is also desirable that the sizes of thecategories or quantization not be too fine so as to allow for reasonableand typical variations and fluctuations in a person's signature,especially for the effects of signing position, comfort, pen weight andsize and the like. In general, increasing the number of signaturecharacteristics characterized by the index value will tend to shortenthe time required to search a database and retrieve the digitizedsignatures therein having matching index values. This generally obtainsbecause the number of records in each subset corresponding to aparticular index value decreases as the number of characteristicsindexed increases, i.e. there are a larger number of subsets eachincluding a smaller number of digitized signature records.

[0161] It is noted that plural signatures may be retrieved from thedigitized signature data base based upon the index value and thosesignatures may then be compared to the transaction digitized signaturefor authentication and, if desired, additional information and/oridentification may be requested to eliminate any ambiguity and identifya specific person.

[0162] Where each category of each indexed characteristic is representedby an alphanumeric character, then the index value for the digitizedsignature is simply the string of applicable alphanumeric characters ina predetermined order of the indexed characteristics. Matching thetransaction digitized signature to the digitized signature records inthe data involves determining the index value for the transactiondigitized signature and retrieving the digitized signature recordshaving index values that match the index value of the transactiondigitized signature.

[0163] It is noted that a further advantage of the described digitizedsignature record requiring 100-300 bytes, as compared to a conventionaldigital signature file of 2-3 kilobytes, is that the time required totransmit the digitized signature record is similarly dramaticallysmaller. Where many digitized signature records are retrieved over acommunication link via a typical 56-kilobyte per second modem, thedifference in the size of the signature record may make the differencebetween the time needed to process a transaction being satisfactory andunsatisfactory. At the server, many more queries can be received andresponded to in any given time and with a particular serverconfiguration where the record size is typically 300 bytes as comparedto 3000 bytes, and up to 30-60 kilobytes for color image or graphicfiles.

[0164]FIG. 11 is a schematic flow diagram illustrating an example votingarrangement 700 employing digitized signatures. Voting process 700starts 702 with a voter being previously registered to vote with eithera conventional graphic or image-based digitized signature 704 a or witha locus-based digitized signature 704 b. On the day(s) of the election,a voter signs in to vote 710 at a polling place by providing a signaturethat is captured as a locus-based digitized signature as describedherein. Such locus-based digitized signature is sometimes referred to asa “signature dynamics” signature and/or a D-SIGN™ signature (a trademarkof AI Technology, Inc.). Process 700 thereafter may take one of severalpaths depending upon the previous registration arrangement and thecurrent registration and/or voting arrangement.

[0165] Where the previous voting arrangement utilizes graphic orimage-based digitized signatures, the locus-based digitized signature isstored and replaces 712 the graphic signature in the database of activevoters and the graphic digitized signature is stored or archived 714 toan archive database. Thus, the graphical signature based voterregistration database is gradually replaced or converted to alocus-based digitized signature database as each voter votes.Optionally, the voter's identification may be verified 716 byconventional means and the voter is allowed to vote 730. The foregoingbuilds a voter database of locus-based digitized signature records aseach voter votes and so is suitable for conversion from a database ofconventional graphic signatures to a database of locus-based digitizedsignature records. Optionally, where the database of graphic signatureshas such signatures stored as color or “gray-scale-rich” graphicalimages, e.g., in TIFF or .BMP bitmap formats, which require about 20-80kilobytes of memory each, conversion 706 thereof to a “monochrome”representation which may reduce the size of the record to about 2-8kilobytes at any time prior to archiving 712 will substantially reducethe storage capacity of the hardware and/or storage media required forstoring such records.

[0166] Where the previous voting arrangement does not utilize digitizedsignatures, the locus-based digitized signature is captured and stored712 in the database of active voters as each voter next votes and thegraphic digitized signature is archived 714 to an archive database.Thus, the conventional voter registration database is gradually replacedor converted to a locus-based digitized signature database as each votervotes, or at least a locus-based digitized signature database isdeveloped in parallel.

[0167] Where the previous voting arrangement utilizes locus-baseddigitized signatures, the locus-based digitized signature captured aseach voter signs in to vote is utilized for verifying 720 the voter'sidentity and registration to vote by comparing the then capturedlocus-based digitized signature and the locus-based digitized signaturestored in the database of active voters. Upon positive verification722P, i.e. the comparison of the transaction digitized signaturecaptured at the polling place is authenticated against the standarddigitized signature retrieved from the database of active voters, thevoter is allowed to vote 730. In the case of negative verification, i.e.the comparison of the transaction digitized signature captured at thepolling place is not authenticated against the standard digitizedsignature retrieved from the database of active voters, the voter is notallowed to vote 730, but may be allowed to vote provisionally 732 andadditional identification may optionally be required 734.

[0168] In any of the foregoing cases, it is preferred that the digitizedsignature captured 710 from the present voter at sign in be compared orcorrelated 740 to the digitized signatures of all voters who havepreviously signed in to vote in the same election. If comparison 740produces a negative correlation 742N with the digitized signatures ofall previous voters, then there is no attempt by that voter to vote morethan once and he is allowed to vote 730. If comparison 740 produces apositive correlation 742P with the digitized signatures of all previousvoters, then there may be an attempt by that voter to vote more thanonce and he is not allowed to vote 730, but may optionally be allowed tovote provisionally 734. Optionally, where another biometric in additionto a digitized signature is captured upon voter sign in, such secondarybiometric data may be acquired 736 from the present voter and stored forlater investigation or displayed for immediate comparison with a likebiometric captured earlier when the person whose signature positivelycorrelated with that of the present voter signed in, as described inapplication Ser. No. 10/127,787 referred to herein above.

[0169] It is understood that the method and apparatus for generating adigitized signature and/or for verifying a digitized signature may findapplication and/or be employed in many different transactions andenvironments. Examples thereof include but are not limited to voting,voter registration, debit and credit card transactions, banking andother financial transactions, insurance transactions, Internet and other“e-commerce” transactions, security and access control, military,defense and government, manufacturing, wholesaling, distributing andretailing, medical treatment and pharmacy, and any other where it isdesired or necessary to verify the identity of a person withappropriately probability. Herein, “transaction” generally refers to anyof the foregoing and “person” generally refers to any person or personsmaking, engaging in or seeking to make or engage in a transaction. Whileany particular example or embodiment herein may be described withreference to a particular context, environment or transaction, e.g.,voter registration and voting, the apparatus and method are not limitedto such contexts, environments and/or transactions.

[0170] The present invention can be embodied as a computer implementedprocess or processes and/or apparatus for performing suchcomputer-implemented process or processes, and can also be embodied inthe form of a tangible storage medium containing a computer program orother machine-readable instructions (herein “computer program”), whereinwhen the computer program is loaded into a computer or other processor(herein “computer”) and/or is executed by the computer, the computerbecomes an apparatus for practicing the invention. Storage media forcontaining such computer program include, for example, floppy disks anddiskettes, compact disks (CD)-ROMs (whether or not writeable), DVDdigital disks, RAM and ROM memories, computer hard drives and back-updrives, and any other storage medium readable by a computer. Theinvention can also be embodied in the form of a computer program, forexample, whether stored in a storage medium or transmitted over atransmission medium such as electrical conductors, fiber optics or otherlight conductors, or by electromagnetic radiation, wherein when thecomputer program is loaded into a computer and/or is executed by thecomputer, the computer becomes an apparatus for practicing theinvention. The invention may be implemented on a general purposemicroprocessor or on a digital processor specifically configured topractice the invention. When a general-purpose microprocessor isemployed, the computer program code configures the circuitry of themicroprocessor to create specific logic circuit arrangements.

[0171] While the present invention has been described in terms of theforegoing example embodiments, variations within the scope and spirit ofthe present invention as defined by the claims following will beapparent to those skilled in the art. For example, while the writingdescribed herein is referred to as a signature, the present method andapparatus may be employed with respect to any writing of any kind,whether character based, alpha-numeric and/or symbolic. In addition,other biometric data, such as fingerprint, palm print, hand and/orfacial geometry, iris, retinal or other eye scans and prints, and thelike, may be utilized as a further identifier of a user or personseeking to register or engage in a transaction.

[0172] The date/time data utilized to provide a precise, and thereforeunique, value for a digitized signature record is relatively easy toverify and is not easily modified or duplicated, especially with timespecified to the millisecond. Even for a local area network where anadministrator may have the ability and opportunity to change (e.g.,falsify) time and date information, the millisecond time data is noteasily duplicated and so can serve as a unique identifier. An advantageof data/time data is that it permits mobility for a user who need not belimited to a particular computer and/or terminal, or a particularInternet port, as is the case where the identity of the hardware is thebasis for security and/or verification.

[0173] Further, the digitized signature software downloaded from theweb-based application may optionally include or be associated with avoice recognition and/or speech synthesis module that is similarlydownloaded to the user's computer for allowing user access to theapplication via spoken commands in response to synthesized speechcommands, such as would be helpful for persons who are visuallyimpaired. The aural messages to the impaired user would includeinstructions and prompts as to when and how to enter data and to signhis signature and whether the signature as signed was sufficientlyaligned with the position and/or pressure sensitive pad to have beencaptured as a locus-based digitized signature. Such speech recognitionand synthesis modules may remain on the user's computer for future use,if desired. Alternatively, where the user's computer contains speechrecognition and/or recognition software, as may be the case where it isincluded in an operating system or other application, the web-basedapplication may be enabled to test for the presence of such software andto utilize it as described. APPENDIX I DIGITIZED SIGNATURE CAPTUREPROGRAM Copyright 2002, AI Technology, Inc. All Rights ReservedStartSign( ) {   CaptureSignature( );   ProduceSignatureData( ); }CaptureSignature( ) {   recycling until sign ending button pressed   {    switch(stylus action)     {       case StylusDown:        StylusDown(Point point);         Break;       case StylusMove:        StylusMove(Point point);         Break;       case StylusUp:        StylusUp(Point point);         Break;     }   } } Struct Point{int x; int y}; Point * m_pointArray; //Array data recording series ofpoints StylusDown(Point point) {   if(!IsWithinSignArea(point))    return;   SetCapture( ); // Capture the stylus until raising.  m_ptPrev = point; // Serves as the MoveTo( ) anchor point for the //LineTo( ) the next point, as the user drags the mouse.  m_pointArray.Add(point); // record the start point of a stroke }StylusMove(Point point) {   if (GetCapture( ) != this) // if during theprocedure of capture signature     return;  if(!IsWithinSignArea(point))     return;   get display area handle‘dc’;   dc.MoveTo(m_ptPrev); //display the locus of signature segment  dc.LineTo(point);   //record the increment value to the previous point  m_pointArray.Add(Point((point.x-m_ptPrev.x),(point.y-m_ptPrev.y)));  m_ptPrev = point; } StylusUp(Point point) {   if (GetCapture( ) !=this) // if during the procedure of capture signature     return;  ReleaseCapture( ); // Release the mouse capture established at  // thebeginning of the mouse drag: OnLButtonDown   if(IsWithinSignArea(point))  {     get display area handle ‘dc’;    dc.MoveTo(m_ptPrev);  //display the orbit of signature segment    dc. LineTo(point);     //record the increment value to the previouspoint    m_pointArray.Add(CPoint((point.x-m_ptPrev.x),(point.y-m_ptPrev.y)));  }   m_pointArray.Add(Point(−256,−256)); //mark the end of this stroke} ProduceSignatureData( ) {   Point pt;   BOOL NewLnId;   USHRTStartPt[2];   CHAR PtDis[2];   GetSamplingValue( );  //Checking theSampling Points per Second   GetBitNum( ); //Calculating Needed Bits forEach Relative Continuous Point   NewLnId = 1; //identifier of starting anew stroke   m_SignData = “”;   //Convert the signature data toHexadecimal string   for (int I=0; I < m_pointArray.GetSize( ); I++)   {    pt = m_pointArray[i];     if(NewLnId == 1)  //record start pointdata of a stroke     {       StartPt[0] = pt.x;       StartPt[1] = pt.y;      NewLnId = 0; //identifier of following by continuous points      //the start point values are recorded with 2 bytes binary value      RecordStartSignatureData(StartPt);     }     else     {      PtDis[0] = pt.x;       PtDis[1] = pt.y;       //for the sequentpoint and end mark, the x and y value are       //recorded with(xBits+yBits) bits binary data       RecordSequenceSignatureData(PtDis);      if(pt.x == −256 && pt.y == −256) //encounter stroke end mark        NewLnId = 1;     }   }   EncryptFinalSignatureData( ); }GetBitNum( ) {   if(xMaxDis>127 ∥ xMinDis<−127)     xBits = 9; //−255−255   else if(xMaxDis>63 ∥ xMinDis<−63)     xBits = 8; //−127 −127  else if(xMaxDis>31 ∥ xMinDis<−31)     xBits = 7; //−63 −63   elseif(xMaxDis>15 ∥ xMinDis<−15)     xBits = 6; //−31 −31   elseif(xMaxDis>7 ∥ xMinDis<−7)     xBits = 5; //−15 −15   else if(xMaxDis>3∥ xMinDis<−3)     xBits = 4; //−7 −7   else if(xMaxDis>1 ∥ xMinDis<−1)    xBits = 3; //−3 −3   else     xBits = 2;   if(yMaxDis>127 ∥yMinDis<−127)     yBits = 9; //−255 −255   else if(yMaxDis>63 ∥yMinDis<−63)     yBits = 8; //−127 −127   else if(yMaxDis>31 ∥yMinDis<−31)     yBits 7; //−63 −63   else if(yMaxDis>15 ∥ yMinDis<−15)    yBits = 6; //−31 −31   else if(yMaxDis>7 ∥ yMinDis<−7)     yBits =5; //−15 −15   else if(yMaxDis>3 ∥ yMinDis<−3)     yBits = 4; //−7 −7  else if(yMaxDis>1 ∥ yMinDis<−1)     yBits = 3; //−3 −3   else    yBits = 2;   if(m_pointArray.GetSize( )>0)   {     m_SignSize =((m_pointArray.GetSize( )−m_StrokeNum)*(xBits+yBits)      +m_StrokeNum*24 + 7)/8 + 2;     // 2 means 1st byte for recordingxBits & yBits, 2nd byte for recoding     // sampling value    //Allocate a memory space to store final compressed signature data    pBitsMem = GlobalLock(GlobalAlloc(GHND, m_SignSize));    FillMemory(pBitsMem,m_SignSize, 0x00);     UCHAR BitNum = (xBits<<4)| yBits;     ((unsigned char*)pBitsMem)[0] = BitNum;     ((unsignedchar*)pBitsMem)[1] = SamplingVal;     NextBitPos = 16;  //from 0   } }Copyright 2002, AI Technology, Inc. All Rights Reserved

[0174] APPENDIX II DIGITIZED SIGNATURE CONVERSION PROGRAM Copyright2002, AI Technology, Inc. All Rights Reserved Struct Point {int x; inty}; Point * m_pointArray; //Array data of series points of signaturelocus float fSignScale; //the scale of signature size vs. bitmap areavoid* pBits;  //Pointer to a binary data memory block with bmp format#define BMPWIDTH 120 #define BMPHEIGHT 60 ConvertToBmp( ) { HBITMAP pBm;//Obtain Signature series of points from database or file m_pointArray =ReadSignData( ); //allocate a block of binary data block pBits =GlobalLock(GlobalAlloc(GHND, (UINT)120*(UINT)60)); FillMemory(pBits,BMPWIDTH * BMPHEIGHT, 0×FF); CreateBmp( ); pBm = CreateBitmap(BMPWIDTH,BMPHEIGHT,1,1,pBits); SaveToBmp(pBm,“sign.bmp”); } CreateBmp( ) { floatxscale, yscale; BOOL NewLnld; int I, xshift, yshift; Point pt, ptPrev;NewLnId = 1; for (I=0; I < m_pointArray.GetSize( ); I++) { pt =m_pointArray.ElementAt(I); if(pt.x == −100 && pt.y == −100) { //filllocus data into a binary data memory block with bmp formatLineTo(ptPrev.x, ptPrev.y); NewLnId = 1; continue; } if(NewLnId = 1) {//fill start point into a binary data memory block of bmp formatMoveTo(pt.x, pt.y); ptPrev = pt; NewLnId = 0; } else { ptPrev.x += pt.x;ptPrev.y += pt.y; //fill locus data into a binary data memory block withbmp format LineTo(ptPrev.x, ptPrev.y); } } } int ox; int oy; MoveTo(x,y) { setPixel(x,y); ox = x; oy = y; } LineTo(x, y) { int ptx, pty;recycle(ptx = (ox to x), pty = (oy to y)) setPixel(ptx, pty); ox = x; oy= y; } setPixel(x, y) { long I, bitpos; int subbit; unsigned charbasebit = 0×80, bytebit; bitpos = y*(BMPWIDTH+8) + x; I = bitpos/8;subbit = bitpos - I*8; bytebit = ˜((basebit)>>subbit); ((unsignedchar*)pBits)[I] &= bytebit; } SaveToBmp(HBITMAP PBitmap, LPTSTR szFile){ HDC   hDC; DWORD  dwPaletteSize=0, dwBmBitsSize, dwDIBSize, dwWritten; BITMAP  Bitmap; HBITMAP  hBitmap = PBitmap; BITMAPFILEHEADERbmfHdr; BITMAPINFOHEADER 1pbi; LPBITMAPINFOHEADER 1pbi; HANDLE   fh,hDib, hPal,hOldPal=NULL; dwPaletteSize = 2*sizeof(RGBQUAD);GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap); bi.biSize    =sizeof(BITMAPINFOHEADER); bi.biWidth   = Bitmap.bmWidth; bi.biHeight   =Bitmap.bmHeight; bi.biPlanes   = 1; bi.biBitCount  = 1; bi.biCompression = BI_RGB; bi.biSizeImage  = 0; bi.biXPelsPerMeter  = 0;bi.biYPelsPerMeter  = 0; bi.biClrUsed   = 0; bi.biClrImportant  = 0;dwBmBitsSize = ((Bitmap.bmWidth+31)/32) * 4 * Bitmap.bmHeight;  hDib =GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+ sizeof(BITMAYINFOHEADER));1pbi = (LPBITMAPINFOHEADER)GlobalLock(hDib); *1pbi = bi; hPal =GetStockObject(DEFAULT_PALETTE); if (hPal) { hDC = ::GCtDC(NULL);hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);RealizePalette(hDC); } GetDIBits(hDC, hBitmap, 0, (UINT)Bitmap.bmHeight, (LPSTR)1pbi+sizeof(BITMAPINFOHEADER)+dwPaletteSize,(LPBITMAPINFO)1pbi, DIB_RGB_COLORS); if (hOldPal) { SelectPalette(hDC,(HPALETTE)hOldPal, TRUE); RealizePalette(hDC); ::ReleaseDC(NULL, hDC); }fh = CreateFile(szFile, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL); if (fh = =INVALID_HANDLE_VALUE)  return; bmfHdr.bfType = 0×4D42; // “BM”dwDIBSize =sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)  +dwPaletteSize + dwBmBitsSize; bmfHdr.bfSize = dwDIBSize;bmfHdr.bfReserved1 = 0; bmfHdr.bfReserved2 = 0; bmfHdr.bfOffBits =(DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPTNFOHEADER) +dwPaletteSize; WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER),&dwWritten, NULL); WriteFile(fh, (LPSTR)lpbi,dwDIBSize-sizeof(BITMAPFILEHEADER), &dwWritten, NULL);GlobalUnlock(hDib); GlobalFree(hDib); CloseHandle(fh); Copyright 2002,AI Technology, Inc. All Rights Reserved

What is claimed is:
 1. A method for representing in an image format asignature stored in a digitized signature record format wherein thesignature is represented in a sequence of strokes each having a startingpoint and an end mark, and wherein locations of points of each strokeare coded as differences in location from either the starting point oran immediately previous point of the stroke, the method comprising: (a)reading a point location from the digitized signature record; (b)determining whether the read point location is the starting point of astroke; (c) if the read point location is the starting point of astroke, then: setting a pixel in the image format located at thelocation of the read point to a display value, storing the pixellocation and display value in the image format, and returning to step(a) for reading the next point location until an end mark is reached;(d) if the read point location is not the starting point of a stroke,then: setting a line of pixels in the image format located in locationsfrom the read point location of the previous read point to the readpoint location of the present read point to a display value, storing thepixel locations and display values of the line of pixels in the imageformat, and returning to step (a) for reading the next point locationuntil an end mark is reached; (e) repeating steps (a) through (d) forall of the strokes of the signature.
 2. The method of claim 1 whereinthe image format is a bitmap format, a BMP format, a TIFF format or aJPEG format.
 3. The method of claim 1 wherein: step (c) furthercomprises displaying the pixel location and display value in the imageformat; and step (d) further comprises displaying the pixel locationsand display values of the line of pixels in the image format.
 4. Astorage medium encoded with machine-readable computer instructions forgenerating a digitized signature record from a signature signed on asigning surface indicating the location of a stylus on the signingsurface comprising: (a) means for causing a computer to record thelocation of the stylus when placed on the signing surface for defining astarting point of each stroke of the signature, wherein the startingpoint of a first stroke of the signature defines the starting point ofthe signature; (b) means for causing the computer to record pointlocations of the stylus on the signing surface relative to a previouspoint until the stylus is lifted off the signing surface, therebydefining a stroke of the signature between the starting point and thelift off point; (c) means for causing the computer to repeat elements(a) through (b) for each subsequent stroke of the signature until thesignature is completely signed; and (d) means for causing the computerto record directly or indirectly a time at which each recorded point isrecorded relative to the time of the starting point of the signature;(e) means for causing the computer to store the locations of thestarting points and subsequent points of each stroke of the signature,and the recorded time, in the digitized signature record, whereby thecomputer is caused to generate a digitized signature record thatincludes at least the positions of the starting points and subsequentpoints of each stroke of a signature in coordinates relative to acoordinate of a previous point thereof and the time point thereof. 5.The storage medium of claim 4 wherein said means for causing thecomputer to record recited in steps (a) and (b) each comprises means forcausing the computer to record the x and y coordinates of the positionof the stylus on the signing surface.
 6. The storage medium of claim 4wherein said means for causing the computer to record directly orindirectly a time comprises either: means for causing the computer toprovide a source of timing data and to record the timing datacorresponding to the time at which each recorded point is recorded; ormeans for causing the computer to record a sampling time or rate atwhich the point locations of the stylus on the signing surface arerecorded.
 7. The storage medium of claim 4 further comprising: means forcausing the computer to generate a relational check code from thelocations of the starting points and subsequent points of each stroke ofthe signature in the digitized signature record; and means for causingthe computer to store the relational check code in the digitizedsignature record.
 8. The storage medium of claim 4 further comprising:means for causing the computer to associate date and time data with thedigitized signature record; means for causing the computer to generate arelational check code from the date and time data and from the locationsof the starting points and subsequent points of each stroke of thesignature in the digitized signature record; and means for causing thecomputer to store the relational check code in the digitized signaturerecord.
 9. The storage medium of claim 8 wherein said means for causingthe computer to associate date and time data includes: means for causingthe computer to communicate the digitized signature record via a server;and means for causing the computer to associate date and time data fromthe server with the digitized signature record.
 10. The storage mediumof claim 4 further comprising: means for causing the computer tocommunicate the digitized signature record via a server; and means forcausing the computer to associate date and time data from the serverwith the digitized signature record.
 11. The storage medium of claim 4wherein said means for causing the computer to store further comprises:means for causing the computer to determine a maximum number of bits forcoding the differences in location of any point location of the stylusrelative to the immediately previous point location thereof; and meansfor causing the computer to store an indication of the determinedmaximum number of bits in the digitized signature record, wherein thelocation of the starting point of each stroke is coded in no more thantwo bytes and the point locations of each stroke are each coded in nomore than one byte.
 12. The storage medium of claim 4 wherein thesigning surface provides an indication of the pressure of the stylus onthe signing surface, said means for causing the computer to record setforth in steps (a) and (b) further comprising means for causing thecomputer to record the pressure of the stylus on the signing surface;and said storage medium further comprising means for causing thecomputer to store in the digitized signature record the pressure of thestylus on the signing surface.
 13. The storage medium of claim 4 furthercomprising means for causing the computer to compare the digitizedsignature record with a reference digitized signature record forauthenticating the signature, and/or verifying the signature, and/oridentifying the signer of the signature.
 14. A method for generating adigitized writing record from a writing written on a writing surfaceproviding an indication of the location of a stylus on the writingsurface comprising: (a) recording the location of the stylus when placedon the writing surface for defining a starting point of each stroke ofthe writing, wherein the starting point of a first stroke of the writingdefines the starting point of the writing; (b) recording point locationsof the stylus on the writing surface until the stylus is lifted off thewriting surface, thereby defining a stroke of the writing between thestarting point and a lift off point; (c) repeating steps (a) and (b) foreach subsequent stroke of the writing until the writing is completelywritten; (d) determining a number of bits for storing the pointlocations of the strokes of the writing and storing the determinednumber in the digitized writing record; (e) storing in the digitizedwriting record a time or rate at which the recorded points are recorded;(f) storing in the digitized writing record the locations of thestarting points of each stroke of the writing; and (g) coding in thedetermined number of bits the locations of the points of each stroke ofthe writing in values relative to a starting point or an immediatelyprevious point thereof and storing same in the digitized writing record;whereby the digitized writing record includes at least the positions ofpoints of a writing in coordinates relative to a starting point or animmediately previous point thereof and the timing thereof.
 15. Themethod of claim 14 wherein said recording recited in steps (a) and (b)each comprises recording the x and y coordinates of the position of thestylus on the writing surface.
 16. The method of claim 14 furthercomprising: generating a relational check code from the locations of thestarting points and points of each stroke of the writing stored in thedigitized writing record; and associating the relational check code withthe digitized writing record.
 17. The method of claim 14 furthercomprising: associating date and time data with the digitized writingrecord; generating a relational check code from the date and time dataand from the locations of the starting points and points of each strokeof the writing stored in the digitized writing record, associating therelational check code with the digitized writing record.
 18. The methodof claim 17 wherein said associating date and time data includes:communicating the digitized writing record via a server; and associatingdate and time data from the server with the digitized writing record.19. The method of claim 14 further comprising: communicating thedigitized writing record via a server; and associating date and timedata from the server with the digitized writing record.
 20. The methodof claim 14 wherein step (d) comprises determining the minimum number ofbits necessary for storing the point locations of the strokes of thewriting and storing the determined minimum number in the digitizedwriting record.
 21. The method of claim 14 wherein step (d) comprises:determining a number of bits for storing the x and y coordinates ofpoint locations of the strokes of the writing; and storing in one byteof the digitized writing record the determined number for storing the xcoordinates and the determined number for storing the y coordinates. 22.The method of claim 14 wherein steps (f) and (g) comprise: storing inrespective first and second bytes of the digitized writing recordrepresentative of a stroke of the writing the x and y coordinates of thestarting point of the stroke; coding in the number of bits determined instep (d) the differences of the x and y coordinates of the points of thestroke of the writing relative to a starting point or to an immediatelyprevious point, and storing same in the digitized writing record;storing in the digitized writing record an end mark value representativeof the end of a stroke; and repeating each of the foregoing three stepsfor each stroke of the writing.
 23. The method of claim 14 furthercomprising representing the writing stored in the digitized writingrecord in an image format, wherein said representing comprises: (a)reading a point location from the digitized writing record; (b)determining whether the read point location is the starting point of astroke; (c) if the read point location is the starting point of astroke, then: setting a pixel in the image format located at thelocation of the read point to a display value, storing the pixellocation and display value in the image format, and returning to step(a) hereof for reading the next point location; (d) if the read pointlocation is not the starting point of a stroke, then: setting a line ofpixels in the image format located in locations from the read pointlocation of the previous read point to the read point location of thepresent read point to a display value, storing the pixel locations anddisplay values of the line of pixels in the image format, and returningto step (a) hereof for reading the next point location; (e) repeatingsteps (a) through (d) for all of the strokes of the writing.
 24. Themethod of claim 14 wherein the writing surface provides an indication ofthe pressure of the stylus on the writing surface, said recording setforth in steps (a) and (b) further comprising recording the pressure ofthe stylus on the writing surface; and said method further comprisingstoring in the digitized writing record the pressure of the stylus onthe writing surface.
 25. The method of claim 14 further comprisingcomparing the digitized writing record with a reference digitizedwriting record for authenticating the writing, and/or verifying thewriting, and/or identifying the writer of the writing.
 26. A method forrepresenting in an image format a writing stored in a digitized writingrecord format wherein the writing is represented in a sequence ofstrokes each having a starting point and an end mark, and whereinlocations of points of each stroke are coded as differences in locationfrom either the starting point or an immediately previous point of thestroke, the method comprising: (a) reading a point location from thedigitized writing record; (b) determining whether the read pointlocation is the starting point of a stroke; (c) if the read pointlocation is the starting point of a stroke, then: setting a pixel in theimage format located at the location of the read point to a displayvalue, storing the pixel location and display value in the image format,and returning to step (a) for reading the next point location until anend mark is reached; (d) if the read point location is not the startingpoint of a stroke, then: setting a line of pixels in the image formatlocated in locations from the read point location of the previous readpoint to the read point location of the present read point to a displayvalue, storing the pixel locations and display values of the line ofpixels in the image format, and returning to step (a) for reading thenext point location until an end mark is reached; (e) repeating steps(a) through (d) for all of the strokes of the writing.
 27. The method ofclaim 26 wherein the image format is a bitmap format, a BMP format, aTIFF format or a JPEG format.
 28. A method for storing and displaying adigitized writing record from a writing written on a writing surfaceproviding an indication of the location of a stylus on the writingsurface, said method comprising: (a) recording the location of thestylus when placed on the writing surface for defining a starting pointof each stroke of the writing, wherein the starting point of a firststroke of the writing defines the starting point of the writing; (b)recording point locations of the stylus on the writing surface until thestylus is lifted off the writing surface, thereby defining a stroke ofthe writing between the starting point and a lift off point; (c)repeating steps (a) and (b) for each subsequent stroke of the writinguntil the writing is completely written; (d) determining a number ofbits for storing the point locations of the strokes of the writing andstoring the determined number in the digitized writing record; (e)storing in the digitized writing record a time or rate at which therecorded points are recorded; (f) storing in the digitized writingrecord the locations of the starting points of each stroke of thewriting; and (g) coding in the determined number of bits the locationsof the points of each stroke of the writing in values relative to astarting point or an immediately previous point thereof and storing samein the digitized writing record; whereby the stored digitized writingrecord includes the positions of points of the writing in coordinatesrelative to the starting point or an immediately previous point thereofand the timing thereof; said method further comprising representing thestored digitized writing in a displayed image, wherein said representingcomprises: (h) reading a point location from the digitized writingrecord; (i) determining whether the read point location is the startingpoint of a stroke; (j) if the read point location is the starting pointof a stroke, then: setting a pixel in the image located at the locationof the read point to a display value, displaying the pixel location anddisplay value in the displayed image; and returning to step (h) hereoffor reading the next point location; (k) if the read point location isnot the starting point of a stroke, then: setting a line of pixels inthe image located in locations from the read point location of theprevious read point to the read point location of the present read pointto a display value, displaying the pixel locations and display values ofthe line of pixels in the displayed image; and returning to step (h)hereof for reading the next point location; (l) repeating steps (h)through (k) for all of the strokes of the digitized writing record;whereby the writing stored in the digitized writing record is displayed.29. The method of claim 28 wherein step (d) comprises determining theminimum number of bits necessary for storing the point locations of thestrokes of the writing and storing the determined minimum number in thedigitized writing record.
 30. The method of claim 28 wherein step (d)comprises: determining a number of bits for storing the x and ycoordinates of point locations of the strokes of the writing; andstoring in one byte of the digitized writing record the determinednumber for storing the x coordinates and the determined number forstoring the y coordinates.
 31. The method of claim 28 wherein steps (f)and (g) comprise: storing in respective first and second bytes of thedigitized writing record representative of a stroke the x and ycoordinates of the starting point of the stroke; coding in the number ofbits determined in step (d) the differences of the x and y coordinatesof the points of the stroke of the writing relative to a starting pointor to an immediately previous point, and storing same in the digitizedwriting record; storing in the digitized writing record an end markvalue representative of the end of a stroke; and repeating each of theforegoing three steps for each stroke of the writing.
 32. A method forgenerating a digitized writing record from a writing signed on a writingsurface comprising: (a) recording the location of a starting point ofeach stroke of the writing, wherein the starting point of a first strokedefines the starting point of the writing; (b) recording point locationson the writing surface until the stylus is lifted off the writingsurface, thereby defining a stroke of the writing; (c) repeating steps(a) and (b) for each subsequent stroke of the writing until the writingis completely written; (d) determining a number of bits for storing thepoint locations of the writing and storing the determined number in thedigitized writing record; (e) storing in the digitized writing record atime or rate at which the recorded points are recorded; (f) storing inthe digitized writing record the locations of the starting points ofeach stroke; and (g) coding in the determined number of bits thelocations of the points of each stroke in values relative to a startingpoint or an immediately previous point thereof and storing same in thedigitized writing record.
 33. The method of claim 32 wherein: saiddetermining of step (d) includes determining the minimum number of bitsneeded for storing the point locations of the writing and storing thedetermined number in one byte of the writing record; and said coding andstoring of step (g) includes storing the determined number of bits ofthe coded point locations in given bytes of the digitized writing recordignoring the defined boundaries of the given bytes.
 34. A method forstoring a digitized writing record from a writing written on a writingsurface providing an indication of the location of a stylus on thewriting surface, said method comprising: (a) recording the location ofthe stylus when placed on the writing surface for defining a startingpoint of each stroke of the writing, wherein the starting point of afirst stroke of the writing defines the starting point of the writing;(b) recording point locations of the stylus on the writing surface untilthe stylus is lifted off the writing surface, thereby defining a strokeof the writing between the starting point and the lift off point; (c)repeating steps (a) and (b) for each subsequent stroke of the writinguntil the writing is completely written; (d) determining a number ofbits needed for storing the x and y coordinates of point locations ofthe strokes of the writing; and (e) storing in one byte of the digitizedwriting record the numbers determined in step (d) for storing the xcoordinates and the y coordinates; (f) storing in the digitized writingrecord a time or rate at which the recorded points are recorded; (g)storing in respective first and second bytes of the digitized writingrecord representative of a stroke of the writing the x and y coordinatesof the starting point of the stroke; (h) coding in the number of bitsdetermined in step (d) the differences of the x and y coordinates of thepoints of the stroke of the writing relative to a starting point or toan immediately previous point, and storing same in the digitized writingrecord; (i) storing in the digitized writing record an end mark valuerepresentative of the end of a stroke; and (j) repeating each of theforegoing steps (g) through (i) for each stroke of the digitizedwriting; whereby the stored digitized writing record includes thepositions of points of the writing in coordinates relative to thestarting point or an immediately previous point thereof and the timingthereof.